It is not a property of iron. Iron

24.11.202227.05.2017

Iron is a metal of medium chemical activity. It is a constituent of many minerals: magnetite, hematite, limonite, siderite, pyrite.

Limonite sample

Chemical and physical properties of iron

Under normal conditions and in its pure form, iron is a silvery-gray solid with a bright metallic luster. Iron is a good electrical and thermal conductor. This can be felt by touching an iron object in a cold room. Since metal conducts heat quickly, it takes most of the heat from human skin in a short period of time, so cold is felt when touched.

pure iron

The melting point of iron is 1538 °C, the boiling point is 2862 °C. The characteristic properties of iron are good ductility and fusibility.

Reacts with simple substances: oxygen, halogens (bromine, iodine, fluorine,), phosphorus, sulfur. When iron is burned, metal oxides are formed. Depending on the reaction conditions and the proportions between the two participants, iron oxides can be varied. Reaction equations:

2Fe + O₂ = 2FeO;

4Fe + 3O₂ = 2Fe₂O₃;

3Fe + 2O₂ = Fe₃O₄.

These reactions take place at high temperatures. you will learn what experiments to study the properties of iron can be done at home.

The reaction of iron with oxygen

For the reaction of iron with oxygen, preheating is necessary. Iron burns with a dazzling flame, scattering - red-hot particles of iron scale Fe₃O₄. The same reaction of iron and oxygen occurs in air, when it is strongly heated by friction during mechanical processing.

When iron is burned in oxygen (or in air), iron scale is formed. Reaction equation:

3Fe + 2O₂ = Fe₃O₄

3Fe + 2O₂ = FeO Fe₂O₃.

Iron oxide is a compound in which iron has different valence values.

Production of iron oxides

Iron oxides are products of the interaction of iron with oxygen. The most famous of them are FeO, Fe₂O₃ and Fe₃O₄.

Iron oxide (III) Fe₂O₃ is an orange-red powder formed during the oxidation of iron in air.

The substance is formed by the decomposition of a ferric salt in air at high temperature. A little iron (III) sulfate is poured into a porcelain crucible, and then it is calcined on the fire of a gas burner. Upon thermal decomposition, ferrous sulfate will decompose into sulfur oxide and iron oxide.

Iron oxide (II, III) Fe₃O₄ is formed by burning powdered iron in oxygen or in air. To obtain oxide, a little fine iron powder mixed with sodium or potassium nitrate is poured into a porcelain crucible. The mixture is ignited with a gas burner. When heated, potassium and sodium nitrates decompose with the release of oxygen. Iron in oxygen burns to form the oxide Fe₃O₄. After the end of combustion, the resulting oxide remains at the bottom of the porcelain cup in the form of iron scale.

Attention! Do not try to repeat these experiments yourself!

Iron(II) oxide FeO is a black powder that is formed by the decomposition of iron oxalate in an inert atmosphere.

Designation - Fe (Iron);
Period - IV;
Group - 8 (VIII);
Atomic mass - 55.845;
Atomic number - 26;
Radius of an atom = 126 pm;
Covalent radius = 117 pm;
Electron distribution - 1s 2 2s 2 2p 6 3s 2 3p 6 3d 6 4s 2 ;
t melting = 1535°C;
boiling point = 2750°C;
Electronegativity (according to Pauling / according to Alpred and Rochov) = 1.83 / 1.64;
Oxidation state: +8, +6, +4, +3, +2, +1, 0;
Density (n.a.) \u003d 7.874 g / cm 3;
Molar volume = 7.1 cm 3 / mol.

Iron compounds:

Iron is the most abundant metal in the Earth's crust (5.1% by mass) after aluminium.

On Earth, iron in a free state is found in small quantities in the form of nuggets, as well as in fallen meteorites.

Industrially, iron is mined at iron ore deposits, from iron-containing minerals: magnetic, red, brown iron ore.

It should be said that iron is a part of many natural minerals, causing their natural color. The color of minerals depends on the concentration and ratio of iron ions Fe 2+ /Fe 3+ , as well as on the atoms surrounding these ions. For example, the presence of impurities of iron ions affects the color of many precious and semi-precious stones: topaz (from pale yellow to red), sapphires (from blue to dark blue), aquamarines (from light blue to greenish blue) and so on.

Iron is found in the tissues of animals and plants, for example, about 5 g of iron is present in the body of an adult. Iron is a vital element, it is part of the hemoglobin protein, participating in the transport of oxygen from the lungs to tissues and cells. With a lack of iron in the human body, anemia (iron deficiency anemia) develops.

Rice. The structure of the iron atom.

The electronic configuration of an iron atom is 1s 2 2s 2 2p 6 3s 2 3p 6 3d 6 4s 2 (see Electronic structure of atoms). In the formation of chemical bonds with other elements, 2 electrons located at the outer 4s level + 6 electrons of the 3d sublevel (8 electrons in total) can participate, therefore, in compounds, iron can take oxidation states +8, +6, +4, +3, +2, +1, (the most common are +3, +2). Iron has an average chemical activity.

Rice. Iron oxidation states: +2, +3.

Physical properties of iron:

silver-white metal;
in its pure form is quite soft and plastic;
has good thermal and electrical conductivity.

Iron exists in the form of four modifications (they differ in the structure of the crystal lattice): α-iron; β-iron; γ-iron; δ-iron.

Chemical properties of iron

reacts with oxygen, depending on the temperature and oxygen concentration, various products or a mixture of iron oxidation products (FeO, Fe 2 O 3, Fe 3 O 4) can be formed:
3Fe + 2O 2 \u003d Fe 3 O 4;
iron oxidation at low temperatures:
4Fe + 3O 2 \u003d 2Fe 2 O 3;
reacts with water vapor:
3Fe + 4H 2 O \u003d Fe 3 O 4 + 4H 2;
finely crushed iron reacts when heated with sulfur and chlorine (iron sulfide and chloride):
Fe + S = FeS; 2Fe + 3Cl 2 \u003d 2FeCl 3;
reacts with silicon, carbon, phosphorus at high temperatures:
3Fe + C = Fe 3 C;
with other metals and with non-metals, iron can form alloys;
iron displaces less active metals from their salts:
Fe + CuCl 2 = FeCl 2 + Cu;
with dilute acids, iron acts as a reducing agent, forming salts:
Fe + 2HCl \u003d FeCl 2 + H 2;
with dilute nitric acid, iron forms various acid reduction products, depending on its concentration (N 2, N 2 O, NO 2).

Obtaining and using iron

Industrial iron is obtained smelting cast iron and steel.

Cast iron is an alloy of iron with impurities of silicon, manganese, sulfur, phosphorus, carbon. The carbon content in cast iron exceeds 2% (in steel, less than 2%).

Pure iron is obtained:

in oxygen converters made of cast iron;
reduction of iron oxides with hydrogen and divalent carbon monoxide;
electrolysis of the corresponding salts.

Cast iron is obtained from iron ores by the reduction of iron oxides. Pig iron is smelted in blast furnaces. Coke is used as a heat source in a blast furnace.

The blast furnace is a very complex technical structure several tens of meters high. It is laid out from refractory bricks and is protected by an external steel casing. As of 2013, the largest blast furnace was built in South Korea by the steel company POSCO at a metallurgical plant in the city of Kwangyang (the volume of the furnace after modernization was 6,000 cubic meters with an annual capacity of 5,700,000 tons).

Rice. Blast furnace.

The process of iron smelting in a blast furnace goes on continuously for several decades, until the furnace reaches its end of life.

Rice. Iron smelting process in a blast furnace.

enriched ores (magnetic, red, brown iron ore) and coke are poured through the top located at the very top of the blast furnace;
the processes of iron recovery from ore under the action of carbon monoxide (II) proceed in the middle part of the blast furnace (shaft) at a temperature of 450-1100 ° C (iron oxides are reduced to metal):
- 450-500°C - 3Fe 2 O 3 + CO = 2Fe 3 O 4 + CO 2;
- 600°C - Fe 3 O 4 + CO = 3FeO + CO 2;
- 800°C - FeO + CO = Fe + CO 2 ;
- part of the ferrous oxide is reduced by coke: FeO + C = Fe + CO.
in parallel, there is a process of reduction of oxides of silicon and manganese (included in iron ore in the form of impurities), silicon and manganese are part of the smelting pig iron:
- SiO 2 + 2C \u003d Si + 2CO;
- Mn 2 O 3 + 3C \u003d 2Mn + 3CO.
during thermal decomposition of limestone (introduced into a blast furnace), calcium oxide is formed, which reacts with oxides of silicon and aluminum contained in the ore:
- CaCO 3 \u003d CaO + CO 2;
- CaO + SiO 2 \u003d CaSiO 3;
- CaO + Al 2 O 3 \u003d Ca (AlO 2) 2.
at 1100°C, the process of iron reduction stops;
below the shaft there is a steam room, the widest part of the blast furnace, below which there is a shoulder, in which coke burns out and liquid smelting products are formed - cast iron and slag, which accumulate at the very bottom of the furnace - the hearth;
in the upper part of the hearth at a temperature of 1500°C, intensive combustion of coke occurs in the jet of blown air: C + O 2 = CO 2 ;
passing through hot coke, carbon monoxide (IV) turns into carbon monoxide (II), which is a reducing agent of iron (see above): CO 2 + C \u003d 2CO;
slags formed by calcium silicates and aluminosilicates are located above the cast iron, protecting it from the action of oxygen;
through special openings located at different levels of the hearth, cast iron and slag are released outside;
Most of the pig iron goes to further processing - steel smelting.

Steel is smelted from cast iron and scrap metal by the converter method (open-hearth is already outdated, although it is still used) or by electric smelting (in electric furnaces, induction furnaces). The essence of the process (iron processing) is to reduce the concentration of carbon and other impurities by oxidation with oxygen.

As mentioned above, the concentration of carbon in steel does not exceed 2%. Due to this, steel, unlike cast iron, is quite easy to forge and roll, which makes it possible to manufacture various products from it with high hardness and strength.

The hardness of steel depends on the carbon content (the more carbon, the harder the steel) in a particular steel grade and heat treatment conditions. During tempering (slow cooling), the steel becomes soft; when quenched (rapidly cooled), the steel becomes very hard.

To give steel the desired specific properties, alloying additives are added to it: chromium, nickel, silicon, molybdenum, vanadium, manganese, and so on.

Cast iron and steel are the most important structural materials in the vast majority of sectors of the national economy.

The biological role of iron:

the body of an adult contains about 5 g of iron;
iron plays an important role in the work of hematopoietic organs;
iron is part of many complex protein complexes (hemoglobin, myoglobin, various enzymes).

Lesson Objectives:

to form an idea of the physical and chemical properties of iron, depending on the degree of oxidation it exhibits and the nature of the oxidizing agent;
to develop the theoretical thinking of students and their ability to predict the properties of matter, based on knowledge of its structure;
develop conceptual thinking of such operations as analysis, comparison, generalization, systematization;
develop such qualities of thinking as objectivity, conciseness and clarity, self-control and activity.

Lesson objectives:

update students' knowledge on the topic: "The structure of the atom";
organize the collective work of students from setting a learning task to the final result (draw up a reference diagram for the lesson);
summarize the material on the topic: “Metals” and consider the properties of iron and its application;
organize independent research work in pairs to study the chemical properties of iron;
organize mutual control of students in the classroom.

Lesson type: learning new material.

Reagents and equipment:

iron (powder, plate, paper clip),
sulfur,
hydrochloric acid,
copper(II) sulfate,
iron crystal lattice,
game posters,
magnet,
a selection of illustrations on the topic,
test tubes,
spirit lamp,
matches,
spoon for burning combustible substances,
geographic Maps.

Lesson structure

Introductory part.
Learning new material.
Homework message.
Consolidation of the studied material.

During the classes

1. Introduction

Organizing time.

Checking for students.

The topic of the lesson. Write the topic on the board and in students' notebooks.

2. Learning new material

What do you think the topic of our lesson today will be?

1. The appearance of iron in human civilization marked the beginning of the Iron Age.

Where did the ancient people get iron at a time when they still did not know how to extract it from ore? Iron, translated from the Sumerian language, is a metal “dropped from the sky, heavenly”. The first iron that mankind encountered was iron from meteorites. He proved for the first time that “iron stones fall from the sky”, in 1775 the Russian scientist P.S. Palace, who brought to St. Petersburg a block of native iron meteorite weighing 600 kg. The largest iron meteorite is the “Goba” meteorite, found in 1920 in Southwest Africa, weighing about 60 tons. Recall the tomb of Tutankhamun: gold, gold. Magnificent work delights, brilliance blinds the eyes. But here is what K. Kerram writes in the book “Gods, Tombs, Scholars” about the small iron amulet of Tutankhamun: the greatest value from the point of view of the history of culture”. Only a few iron items were found in the tomb of the pharaoh, among them an iron amulet of the god Horus, a small dagger with an iron blade and a golden handle, a small iron bench “Urs”.

Scientists suggest that it was the countries of Asia Minor, where the Hittite tribes lived, that were the place where ferrous metallurgy appeared. Iron came to Europe from Asia Minor as early as the 1st millennium BC; Thus began the Iron Age in Europe.

The famous damask steel (or damask steel) was made in the East back in the time of Aristotle (4th century BC). But the technology of its manufacture was kept secret for many centuries.

I dreamed of a different sadness
About gray Damascus steel.
I saw the steel temper
As one of the young slaves
Chose, fed him,
So that the flesh of his strength was recruited.
Waiting for the due date
And then a hot blade
Immersed in muscular flesh
They took out the finished blade.
Stronger than steel, did not see the East,
Stronger than steel and bitterer than sorrow.

Since damask steel is a steel with very high hardness and elasticity, products made from it have the ability not to blunt when sharply sharpened. The Russian metallurgist P.P. revealed the secret of damask steel. Anosov. He very slowly cooled hot steel in a special solution of technical oil heated to a certain temperature; during the cooling process, the steel was forged.

(Demonstration of drawings.)

Iron - silver gray metal	Iron - silver gray metal
These nails are made of iron	Steel is used in the automotive industry
Steel is used to make medical instruments	Steel is used to make locomotives
	All metals are susceptible to corrosion
All metals are susceptible to corrosion

2. The position of iron in PSCHEM.

We find out the position of iron in the PSCM, the charge of the nucleus and the distribution of electrons in the atom.

3. Physical properties of iron.

What physical properties of iron do you know?

Iron is a silvery-white metal with a melting point of 1539 o C. It is very ductile, therefore it is easily processed, forged, rolled, stamped. Iron has the ability to be magnetized and demagnetized, therefore it is used as the cores of electromagnets in various electrical machines and apparatuses. It can be given greater strength and hardness by methods of thermal and mechanical action, for example, by quenching and rolling.

There are chemically pure and technically pure iron. Technically pure iron, in fact, is a low-carbon steel, it contains 0.02 -0.04% carbon, and even less oxygen, sulfur, nitrogen and phosphorus. Chemically pure iron contains less than 0.01% impurities. chemically pure iron silvery-gray, shiny, in appearance very similar to platinum metal. Chemically pure iron is resistant to corrosion (remember what is corrosion? Demonstration of a corrosive nail) and resists well to acids. However, insignificant fractions of impurities deprive it of these precious properties.

4. Chemical properties of iron.

Based on the knowledge about the chemical properties of metals, what do you think the chemical properties of iron will be?

Demonstration of experiences.

The interaction of iron with sulfur.

Practical work.

The interaction of iron with hydrochloric acid.
Interaction of iron with copper (II) sulfate.

5. The use of iron.

Conversation on:

- How do you think up, what is the distribution of iron in nature?

Iron is one of the most common elements in nature. In the earth's crust, its mass fraction is 5.1%, according to this indicator, it is second only to oxygen, silicon and aluminum. A lot of iron is also found in celestial bodies, which is established from the data of spectral analysis. In samples of lunar soil, which were delivered by the automatic station "Luna", iron was found in an unoxidized state.

Iron ores are quite widespread on Earth. The names of the mountains in the Urals speak for themselves: High, Magnetic, Iron. Agricultural chemists find iron compounds in soils.

In what form does iron occur in nature?

Iron is found in most rocks. To obtain iron, iron ores with an iron content of 30-70% or more are used. The main iron ores are: magnetite - Fe 3 O 4 contains 72% iron, deposits are found in the South Urals, the Kursk magnetic anomaly; hematite - Fe 2 O 3 contains up to 65% iron, such deposits are found in the Krivoy Rog region; limonite - Fe 2 O 3 * nH 2 O contains up to 60% iron, deposits are found in the Crimea; pyrite - FeS 2 contains approximately 47% iron, deposits are found in the Urals. (Working with contour maps).

What is the role of iron in human and plant life?

Biochemists have discovered the important role of iron in the life of plants, animals and humans. Being part of an extremely complex organic compound called hemoglobin, iron determines the red color of this substance, which in turn determines the color of the blood of humans and animals. The body of an adult contains 3 g of pure iron, 75% of which is part of hemoglobin. The main role of hemoglobin is the transfer of oxygen from the lungs to the tissues, and in the opposite direction - CO 2.

Plants also need iron. It is part of the cytoplasm, participates in the process of photosynthesis. Plants grown on an iron-free substrate have white leaves. A small addition of iron to the substrate - and they turn green. Moreover, it is worth smearing a white sheet with a solution of salt containing iron, and soon the smeared place turns green.

So from the same reason - the presence of iron in juices and tissues - the leaves of plants turn green cheerfully and the cheeks of a person blush brightly.

Approximately 90% of the metals used by mankind are iron-based alloys. There is a lot of iron smelted in the world, about 50 times more than aluminum, not to mention other metals. Iron-based alloys are universal, technologically advanced, affordable, and cheap. Iron has long to be the foundation of civilization.

3. Post home stuff

14, ex. No. 6, 8, 9 (according to the workbook for the textbook by O.S Gabrielyan “Chemistry 9”, 2003).

4. Consolidation of the studied material

Using the reference diagram written on the board, draw a conclusion: what is iron and what are its properties?
Graphic dictation (prepare in advance leaflets with a drawn straight line, divided into 8 segments and numbered according to the questions of the dictation. Mark with a hut “^” on the segment the number of the position that is considered correct).

Option 1.

Iron is an active alkali metal.
Iron is easily forged.
Iron is part of the bronze alloy.
The outer energy level of an iron atom has 2 electrons.
Iron interacts with dilute acids.
With halogens it forms halides with an oxidation state of +2.
Iron does not interact with oxygen.
Iron can be obtained by electrolysis of its salt melt.


1	2	3	4	5	6	7	8

Option 2.

Iron is a silver-white metal.
Iron does not have the ability to be magnetized.
Iron atoms exhibit oxidizing properties.
The outer energy level of an iron atom has 1 electron.
Iron displaces copper from solutions of its salts.
With halogens, it forms compounds with an oxidation state of +3.
With a solution of sulfuric acid forms iron sulfate (III).
Iron does not corrode.


1	2	3	4	5	6	7	8

After completing the assignment, students change their work and check it (the answers to the work are posted on the board, or show through the projector).

Mark criteria:

"5" - 0 errors,
“4” - 1-2 errors,
"3" - 3-4 errors,
"2" - 5 or more errors.

Used Books

Gabrielyan O.S. Chemistry grade 9. – M.: Bustard, 2001.
Gabrielyan O.S. The book for the teacher. – M.: Bustard, 2002.
Gabrielyan O.S. Chemistry grade 9. Workbook. – M.: Bustard, 2003.
Education industry. Digest of articles. Issue 3. - M .: MGIU, 2002.
Malyshkina V. Entertaining chemistry. - St. Petersburg, "Trigon", 2001.
Program-methodical materials. Chemistry 8-11 grades. – M.: Bustard, 2001.
Stepin B.D., Alikberova L.Yu. Chemistry book for home reading. – M.: Chemistry, 1995.
I'm going to chemistry class. The book for the teacher. – M.: “First of September”, 2000.

Applications

Do you know that?

Iron is one of the most important elements of life. Blood contains iron, and it is iron that determines the color of blood, as well as its main property - the ability to bind and release oxygen. This ability is possessed by a complex compound - heme - an integral part of the hemoglobin molecule. In addition to hemoglobin, iron in our body is also in myoglobin, a protein that stores oxygen in the muscles. There are also iron-containing enzymes.

Near the city of Delhi in India, there is an iron column without the slightest speck of rust, although its age is almost 2800 years. This is the famous Kutub column, about seven meters high and weighing 6.5 tons. The inscription on the column says that it was erected in the 9th century. BC e. The rusting of iron - the formation of iron metahydroxide - is associated with its interaction with moisture and oxygen in the air.

However, this reaction, in the absence of various impurities in iron, and primarily carbon, silicon and sulfur, does not proceed. The column was made of very pure metal: iron in the column turned out to be 99.72%. This explains its durability and corrosion resistance.

In 1934, an article appeared in the "Mining Journal" "Improvement of iron and steel by ... rusting in the ground." The method of turning iron into steel through rusting in the earth has been known to people since ancient times. For example, the Circassians in the Caucasus buried strip iron in the ground, and after digging it out after 10-15 years, they forged their sabers from it, which could even cut through a gun barrel, shield, and bones of the enemy.

Hematite

Hematite, or red iron ore - the main ore of the main metal of our time - iron. The iron content in it reaches 70%. Hematite has been known for a long time. In Babylon and Ancient Egypt, it was used in jewelry, for the manufacture of seals, along with chalcedony served as a favorite material as a carved stone. Alexander the Great had a ring inlaid with hematite, which he believed made him invulnerable in battle. In antiquity and in the Middle Ages, hematite was known as a blood-stopping medicine. Powder from this mineral has been used for gold and silver products since ancient times.

The name of the mineral comes from the Greek deta- blood, which is associated with the cherry or wax-red color of the powder of this mineral.

An important feature of the mineral is the ability to retain color and transfer it to other minerals, into which at least a small admixture of hematite gets. The pink color of the granite columns of St. Isaac's Cathedral is the color of feldspars, which in turn are painted with finely powdered hematite. The picturesque patterns of jasper used in the decoration of the metro stations of the capital, the orange and pink cornelians of the Crimea, the coral-red interlayers of sylvin and carnallite in the salt strata - all owe their color to hematite.

Red paint has long been made from hematite. All famous frescoes made 15-20 thousand years ago - the wonderful bison of the Altamira cave and mammoths from the famous Cape cave - are made with both brown oxides and iron hydroxides.

Magnetite

Magnetite, or magnetic iron ore - a mineral containing 72% iron. It is the richest iron ore. The remarkable thing about this mineral is its natural magnetism - the property due to which it was discovered.

According to the Roman scientist Pliny, magnetite is named after the Greek shepherd Magnes. Magnes grazed the herd near the hill above the river. Hindu in Thessaly. Suddenly, a staff with an iron tip and sandals lined with nails were attracted to itself by a mountain composed of solid gray stone. The mineral magnetite, in turn, gave the name to the magnet, the magnetic field and the whole mysterious phenomenon of magnetism, which has been closely studied since the time of Aristotle to this day.

The magnetic properties of this mineral are still used today, primarily to search for deposits. This is how unique iron deposits were discovered in the area of the Kursk Magnetic Anomaly (KMA). The mineral is heavy: an apple-sized sample of magnetite weighs 1.5 kg.

In ancient times, magnetite was endowed with all sorts of healing properties and the ability to work miracles. It was used to extract metal from wounds, and Ivan the Terrible among his treasures, along with other stones, kept his unremarkable crystals.

Pyrite is a mineral similar to fire.

Pyrite - one of those minerals, seeing which you want to exclaim: "Is it really so?" It is hard to believe that the highest class of cutting and polishing that strikes us in man-made products, in pyrite crystals, is a generous gift of nature.

Pyrite got its name from the Greek word "pyros" - fire, which is associated with its property to spark when struck by steel objects. This beautiful mineral strikes with a golden color, a bright sheen on almost always clear edges. Due to its properties, pyrite has been known since ancient times, and during epidemics of the gold rush, pyrite sparkles in a quartz vein turned more than one hot head. Even now, novice stone lovers often mistake pyrite for gold.

Pyrite is an omnipresent mineral: it is formed from magma, from vapors and solutions, and even from sediments, each time in specific forms and combinations. A case is known when, over several decades, the body of a miner who fell into a mine turned into pyrite. There is a lot of iron in pyrite - 46.5%, but it is expensive and unprofitable to extract it.

Story

Iron as an instrumental material has been known since ancient times. The oldest iron products found during archaeological excavations date back to the 4th millennium BC. e. and belong to the ancient Sumerian and ancient Egyptian civilizations. These are made of meteoric iron, that is, an alloy of iron and nickel (the content of the latter ranges from 5 to 30%), jewelry from Egyptian tombs (about 3800 BC) and a dagger from the Sumerian city of Ur (about 3100 BC). e.). Apparently, one of the names of iron in Greek and Latin comes from the celestial origin of meteoric iron: “sider” (which means “starry”).

Products from iron obtained by smelting have been known since the time of the settlement of the Aryan tribes from Europe to Asia, the islands of the Mediterranean Sea, and beyond (the end of the 4th and 3rd millennium BC). The oldest known iron tools are steel blades found in the masonry of the pyramid of Cheops in Egypt (built around 2530 BC). As excavations in the Nubian desert have shown, already in those days the Egyptians, trying to separate the mined gold from heavy magnetite sand, calcined ore with bran and similar substances containing carbon. As a result, a layer of doughy iron floated on the surface of the gold melt, which was processed separately. Tools were forged from this iron, including those found in the pyramid of Cheops. However, after the grandson of Cheops Menkaur (2471-2465 BC), turmoil occurred in Egypt: the nobility, led by the priests of the god Ra, overthrew the ruling dynasty, and a leapfrog of usurpers began, ending with the accession of the pharaoh of the next dynasty, Userkar, whom the priests declared to be the son and incarnation the god Ra himself (since then this has become the official status of the pharaohs). During this turmoil, the cultural and technical knowledge of the Egyptians fell into decay, and, just as the art of building the pyramids degraded, the technology of iron production was lost, to the point that later, while exploring the Sinai Peninsula in search of copper ore, the Egyptians did not pay any attention to iron ore deposits there, but received iron from neighboring Hittites and Mitannians.

The first mastered the production of iron Hatt, this is indicated by the oldest (2nd millennium BC) mention of iron in the texts of the Hittites, who founded their empire on the territory of the Hatt (modern Anatolia in Turkey). So, in the text of the Hittite king Anitta (about 1800 BC) it says:

When I went on a campaign to the city of Puruskhanda, a man from the city of Puruskhanda came to bow to me (...?) and he presented me with 1 iron throne and 1 iron scepter (?) as a sign of humility (?) ...

(source: Giorgadze G. G.// Bulletin of ancient history. 1965. No. 4.)

In ancient times, khalibs were reputed to be masters of iron products. The legend of the Argonauts (their campaign to Colchis took place about 50 years before the Trojan War) tells that the king of Colchis, Eet, gave Jason an iron plow to plow the field of Ares, and his subjects, the halibers, are described:

They do not plow the land, do not plant fruit trees, do not graze herds in rich meadows; they extract ore and iron from the uncultivated land and barter food for them. The day does not begin for them without hard work, they spend in the darkness of the night and thick smoke, working all day ...

Aristotle described their method of obtaining steel: “the Khalibs washed the river sand of their country several times - thereby separating black concentrate (a heavy fraction consisting mainly of magnetite and hematite), and melted it in furnaces; the metal thus obtained had a silvery color and was stainless."

Magnetite sands, which are often found along the entire coast of the Black Sea, were used as raw materials for steel smelting: these magnetite sands consist of a mixture of fine grains of magnetite, titanium-magnetite or ilmenite, and fragments of other rocks, so that the steel smelted by the Khalibs was alloyed, and had excellent properties. Such a peculiar way of obtaining iron suggests that the Khalibs only spread iron as a technological material, but their method could not be a method for the widespread industrial production of iron products. However, their production served as an impetus for the further development of iron metallurgy.

In the deepest antiquity, iron was valued more than gold, and according to the description of Strabo, African tribes gave 10 pounds of gold for 1 pound of iron, and according to the studies of the historian G. Areshyan, the cost of copper, silver, gold and iron among the ancient Hittites was in the ratio 1: 160 : 1280: 6400. In those days, iron was used as a jewelry metal, thrones and other regalia of royal power were made from it: for example, in the biblical book Deuteronomy 3.11, an “iron bed” of the Rephaim king Og is described.

In the tomb of Tutankhamen (circa 1350 BC) was found a dagger made of iron in a gold frame - possibly a gift from the Hittites for diplomatic purposes. But the Hittites did not strive for the widespread dissemination of iron and its technologies, which is also evident from the correspondence of the Egyptian pharaoh Tutankhamun and his father-in-law Hattusil, the king of the Hittites, that has come down to us. The pharaoh asks to send more iron, and the king of the Hittites evasively answers that the iron reserves have run out, and the blacksmiths are busy with agricultural work, so he cannot fulfill the request of the royal son-in-law, and sends only one dagger from “good iron” (that is, steel). As you can see, the Hittites tried to use their knowledge to achieve military advantages, and did not give others the opportunity to catch up with them. Apparently, therefore, iron products became widespread only after the Trojan War and the fall of the Hittites, when, thanks to the trading activity of the Greeks, iron technology became known to many, and new iron deposits and mines were discovered. So the Bronze Age was replaced by the Iron Age.

According to Homer's descriptions, although during the Trojan War (circa 1250 BC) weapons were mostly made of copper and bronze, iron was already well known and in great demand, although more as a precious metal. For example, in the 23rd song of the Iliad, Homer says that Achilles awarded the winner in a discus throwing competition with an iron cry disc. The Achaeans mined this iron from the Trojans and neighboring peoples (Iliad 7.473), including from the Khalibs, who fought on the side of the Trojans:

“Other men of the Achaeans bought wine with me,
Those for ringing copper, for gray iron changed,
Those for ox-skins or high-horned oxen,
Those for their captives. And a merry feast is prepared ... "

Perhaps iron was one of the reasons that prompted the Achaean Greeks to move to Asia Minor, where they learned the secrets of its production. And excavations in Athens showed that already around 1100 BC. e. and later iron swords, spears, axes, and even iron nails were already widespread. The biblical book of Joshua 17:16 (cf. Judges 14:4) describes that the Philistines (biblical "PILISTIM", and these were proto-Greek tribes related to the later Hellenes, mainly Pelasgians) had many iron chariots, that is, in this iron has already become widely used in large quantities.

Homer in the Iliad and the Odyssey calls iron "a hard metal", and describes the hardening of tools:

“A quick forger, having made an ax or an ax,
Metal into the water, heating it up so that it doubles
He had a fortress, immerses ... "

Homer calls iron difficult, because in ancient times the main method of obtaining it was the raw-blowing process: alternating layers of iron ore and charcoal were calcined in special furnaces (forges - from the ancient "Horn" - a horn, a pipe, originally it was just a pipe dug in the ground , usually horizontally in the slope of a ravine). In the hearth, iron oxides are reduced to metal by hot coal, which takes away oxygen, oxidizing to carbon monoxide, and as a result of such calcination of ore with coal, doughy bloom (spongy) iron was obtained. Kritsu was cleaned of slag by forging, squeezing out impurities with strong hammer blows. The first hearths had a relatively low temperature - noticeably lower than the melting point of cast iron, so the iron turned out to be relatively low-carbon. In order to obtain strong steel, it was necessary to calcinate and forge the iron bar with coal many times, while the surface layer of the metal was additionally saturated with carbon and hardened. This was how “good iron” was obtained - and although it required a lot of work, the products obtained in this way were significantly stronger and harder than bronze ones.

Later, they learned how to make more efficient furnaces (in Russian - blast furnace, domnitsa) for steel production, and used furs to supply air to the furnace. Already the Romans were able to bring the temperature in the furnace to the melting of steel (about 1400 degrees, and pure iron melts at 1535 degrees). In this case, cast iron is formed with a melting point of 1100-1200 degrees, which is very brittle in the solid state (not even amenable to forging) and does not have the elasticity of steel. It was originally considered a harmful by-product. pig iron, in Russian, pig iron, ingots, where, in fact, the word cast iron comes from), but then it turned out that when remelted in a furnace with increased air blowing through it, cast iron turns into good quality steel, as excess carbon burns out. Such a two-stage process for the production of steel from cast iron turned out to be simpler and more profitable than bloomery, and this principle has been used without much change for many centuries, remaining to this day the main method for the production of iron materials.

Bibliography: Karl Bucks. Wealth of the earth's interior. M .: Progress, 1986, p. 244, chapter "Iron"

origin of name

There are several versions of the origin of the Slavic word "iron" (Belarusian zhalez, Ukrainian zalizo, old Slav. iron, bulg. iron, Serbohorv. zhezo, Polish. Zelazo, Czech železo, Slovenian zelezo).

One of the etymologies connects Praslav. *ZelEzo with the Greek word χαλκός , which meant iron and copper, according to another version *ZelEzo akin to words *zely"turtle" and *eye"rock", with the general seme "stone". The third version suggests an ancient borrowing from an unknown language.

The Germanic languages borrowed the name iron (Gothic. eisarn, English iron, German Eisen, netherl. ijzer, dat. jern, swedish jarn) from Celtic.

Pra-Celtic word *isarno-(> OE iarn, OE Bret hoiarn), probably goes back to Proto-IE. *h 1 esh 2 r-no- "bloody" with the semantic development "bloody" > "red" > "iron". According to another hypothesis, this word goes back to pra-i.e. *(H)ish 2ro- "strong, holy, possessing supernatural power" .

ancient greek word σίδηρος , may have been borrowed from the same source as the Slavic, Germanic, and Baltic words for silver.

The name of natural iron carbonate (siderite) comes from lat. sidereus- stellar; indeed, the first iron that fell into the hands of people was of meteoric origin. Perhaps this coincidence is not accidental. In particular, the ancient Greek word sideros (σίδηρος) for iron and latin sidus, meaning "star", probably have a common origin.

isotopes

Natural iron consists of four stable isotopes: 54 Fe (isotopic abundance 5.845%), 56 Fe (91.754%), 57 Fe (2.119%) and 58 Fe (0.282%). More than 20 unstable iron isotopes with mass numbers from 45 to 72 are also known, the most stable of which are 60 Fe (half-life according to data updated in 2009 is 2.6 million years), 55 Fe (2.737 years), 59 Fe ( 44.495 days) and 52 Fe (8.275 hours); the remaining isotopes have half-lives of less than 10 minutes.

The iron isotope 56 Fe is among the most stable nuclei: all of the following elements can reduce the binding energy per nucleon by decay, and all previous elements, in principle, could reduce the binding energy per nucleon due to fusion. It is believed that a series of synthesis of elements in the cores of normal stars ends with iron (see Iron star), and all subsequent elements can be formed only as a result of supernova explosions.

Geochemistry of iron

Hydrothermal source with ferruginous water. Iron oxides turn water brown

Iron is one of the most common elements in the solar system, especially on the terrestrial planets, in particular on Earth. A significant part of the iron of the terrestrial planets is located in the cores of the planets, where its content is estimated to be about 90%. The content of iron in the earth's crust is 5%, and in the mantle about 12%. Of the metals, iron is second only to aluminum in terms of abundance in the crust. At the same time, about 86% of all iron is in the core, and 14% in the mantle. The content of iron increases significantly in the igneous rocks of the basic composition, where it is associated with pyroxene, amphibole, olivine and biotite. In industrial concentrations, iron accumulates during almost all exogenous and endogenous processes occurring in the earth's crust. In sea water, iron is contained in very small amounts of 0.002-0.02 mg / l. In river water, it is slightly higher - 2 mg / l.

Geochemical properties of iron

The most important geochemical feature of iron is that it has several oxidation states. Iron in a neutral form - metallic - composes the core of the earth, possibly present in the mantle and very rarely found in the earth's crust. Ferrous iron FeO is the main form of iron in the mantle and the earth's crust. Oxide iron Fe 2 O 3 is characteristic of the uppermost, most oxidized, parts of the earth's crust, in particular, sedimentary rocks.

In terms of crystal chemical properties, the Fe 2+ ion is close to the Mg 2+ and Ca 2+ ions, other main elements that make up a significant part of all terrestrial rocks. Due to their crystal chemical similarity, iron replaces magnesium and, in part, calcium in many silicates. The content of iron in minerals of variable composition usually increases with decreasing temperature.

iron minerals

A large number of ores and minerals containing iron are known. Of the greatest practical importance are red iron ore (hematite, Fe 2 O 3; contains up to 70% Fe), magnetic iron ore (magnetite, FeFe 2 O 4, Fe 3 O 4; contains 72.4% Fe), brown iron ore or limonite (goethite and hydrogoethite, FeOOH and FeOOH nH 2 O, respectively). Goethite and hydrogoethite are most often found in weathering crusts, forming the so-called "iron hats", the thickness of which reaches several hundred meters. They can also be of sedimentary origin, falling out of colloidal solutions in lakes or coastal areas of the seas. In this case, oolitic, or legume, iron ores are formed. Vivianite Fe 3 (PO 4) 2 8H 2 O is often found in them, forming black elongated crystals and radial-radiant aggregates.

Iron sulfides are also widespread in nature - pyrite FeS 2 (sulfur or iron pyrite) and pyrrhotite. They are not iron ore - pyrite is used to produce sulfuric acid, and pyrrhotite often contains nickel and cobalt.

In terms of iron ore reserves, Russia ranks first in the world. The content of iron in sea water is 1·10 −5 -1·10 −8%.

Other common iron minerals are:

Siderite - FeCO 3 - contains approximately 35% iron. It has a yellowish-white (with a gray or brown tint in case of contamination) color. The density is 3 g / cm³ and the hardness is 3.5-4.5 on the Mohs scale.
Marcasite - FeS 2 - contains 46.6% iron. It occurs in the form of yellow, like brass, bipyramidal rhombic crystals with a density of 4.6-4.9 g / cm³ and a hardness of 5-6 on the Mohs scale.
Lollingite - FeAs 2 - contains 27.2% iron and occurs in the form of silver-white bipyramidal rhombic crystals. Density is 7-7.4 g / cm³, hardness is 5-5.5 on the Mohs scale.
Mispikel - FeAsS - contains 34.3% iron. It occurs in the form of white monoclinic prisms with a density of 5.6-6.2 g / cm³ and a hardness of 5.5-6 on the Mohs scale.
Melanterite - FeSO 4 7H 2 O - is less common in nature and is a green (or gray due to impurities) monoclinic crystals with a vitreous luster, fragile. The density is 1.8-1.9 g / cm³.
Vivianite - Fe 3 (PO 4) 2 8H 2 O - occurs in the form of blue-gray or green-gray monoclinic crystals with a density of 2.95 g / cm³ and a hardness of 1.5-2 on the Mohs scale.

In addition to the above iron minerals, there are, for example:

Main deposits

According to the US Geological Survey (2011 estimate), the world's proven reserves of iron ore are about 178 billion tons. The main iron deposits are in Brazil (1st place), Australia, USA, Canada, Sweden, Venezuela, Liberia, Ukraine, France, India. In Russia, iron is mined at the Kursk Magnetic Anomaly (KMA), the Kola Peninsula, Karelia and Siberia. Recently, bottom oceanic deposits have acquired a significant role, in which iron, together with manganese and other valuable metals, is found in nodules.

Receipt

In industry, iron is obtained from iron ore, mainly from hematite (Fe 2 O 3) and magnetite (FeO Fe 2 O 3).

There are various ways to extract iron from ores. The most common is the domain process.

The first stage of production is the reduction of iron with carbon in a blast furnace at a temperature of 2000 ° C. In a blast furnace, carbon in the form of coke, iron ore in the form of sinter or pellets, and flux (such as limestone) are fed in from above and are met by a stream of injected hot air from below.

In the furnace, carbon in the form of coke is oxidized to carbon monoxide. This oxide is formed during combustion in a lack of oxygen:

In turn, carbon monoxide recovers iron from the ore. To make this reaction go faster, heated carbon monoxide is passed through iron (III) oxide:

Calcium oxide combines with silicon dioxide, forming a slag - calcium metasilicate:

Slag, unlike silicon dioxide, is melted in a furnace. Lighter than iron, slag floats on the surface - this property allows you to separate the slag from the metal. The slag can then be used in construction and agriculture. Iron melt obtained in a blast furnace contains quite a lot of carbon (cast iron). Except in such cases, when cast iron is used directly, it requires further processing.

Excess carbon and other impurities (sulphur, phosphorus) are removed from cast iron by oxidation in open-hearth furnaces or in converters. Electric furnaces are also used for smelting alloyed steels.

In addition to the blast furnace process, the process of direct production of iron is common. In this case, pre-crushed ore is mixed with special clay to form pellets. The pellets are roasted and treated in a shaft furnace with hot methane conversion products that contain hydrogen. Hydrogen easily reduces iron:

while there is no contamination of iron with impurities such as sulfur and phosphorus, which are common impurities in coal. Iron is obtained in solid form, and then melted down in electric furnaces.

Chemically pure iron is obtained by electrolysis of solutions of its salts.

Physical properties

The phenomenon of polymorphism is extremely important for steel metallurgy. It is thanks to the α-γ transitions of the crystal lattice that the heat treatment of steel occurs. Without this phenomenon, iron as the basis of steel would not have received such widespread use.

Iron is a moderately refractory metal. In a series of standard electrode potentials, iron stands before hydrogen and easily reacts with dilute acids. Thus, iron belongs to the metals of medium activity.

The melting point of iron is 1539 °C, the boiling point is 2862 °C.

Chemical properties

Characteristic oxidation states

Acid does not exist in its free form - only its salts have been obtained.

For iron, the oxidation states of iron are characteristic - +2 and +3.

The oxidation state +2 corresponds to black oxide FeO and green hydroxide Fe(OH) 2 . They are basic. In salts, Fe(+2) is present as a cation. Fe(+2) is a weak reducing agent.

+3 oxidation states correspond to red-brown Fe 2 O 3 oxide and brown Fe(OH) 3 hydroxide. They are amphoteric in nature, although their acidic and basic properties are weakly expressed. Thus, Fe 3+ ions are completely hydrolyzed even in an acidic environment. Fe (OH) 3 dissolves (and even then not completely), only in concentrated alkalis. Fe 2 O 3 reacts with alkalis only when fused, giving ferrites (formal salts of an acid that does not exist in a free form of acid HFeO 2):

Iron (+3) most often exhibits weak oxidizing properties.

The +2 and +3 oxidation states easily transition between themselves when the redox conditions change.

In addition, there is Fe 3 O 4 oxide, the formal oxidation state of iron in which is +8/3. However, this oxide can also be considered as iron (II) ferrite Fe +2 (Fe +3 O 2) 2 .

There is also an oxidation state of +6. The corresponding oxide and hydroxide do not exist in free form, but salts - ferrates (for example, K 2 FeO 4) have been obtained. Iron (+6) is in them in the form of an anion. Ferrates are strong oxidizing agents.

Properties of a simple substance

When stored in air at temperatures up to 200 ° C, iron is gradually covered with a dense film of oxide, which prevents further oxidation of the metal. In moist air, iron is covered with a loose layer of rust, which does not prevent the access of oxygen and moisture to the metal and its destruction. Rust does not have a constant chemical composition; approximately its chemical formula can be written as Fe 2 O 3 xH 2 O.

Iron(II) compounds

Iron oxide (II) FeO has basic properties, it corresponds to the base Fe (OH) 2. Salts of iron (II) have a light green color. When stored, especially in moist air, they turn brown due to oxidation to iron (III). The same process occurs during storage of aqueous solutions of iron(II) salts:

Of the iron (II) salts in aqueous solutions, Mohr's salt is stable - double ammonium and iron (II) sulfate (NH 4) 2 Fe (SO 4) 2 6H 2 O.

Potassium hexacyanoferrate (III) K 3 (red blood salt) can serve as a reagent for Fe 2+ ions in solution. When Fe 2+ and 3− ions interact, turnbull blue precipitates:

For the quantitative determination of iron (II) in solution, phenanthroline Phen is used, which forms a red FePhen 3 complex with iron (II) (light absorption maximum - 520 nm) in a wide pH range (4-9).

Iron(III) compounds

Iron(III) compounds in solutions are reduced by metallic iron:

Iron (III) is able to form double sulfates with singly charged alum-type cations, for example, KFe (SO 4) 2 - potassium iron alum, (NH 4) Fe (SO 4) 2 - iron ammonium alum, etc.

For qualitative detection of iron(III) compounds in solution, the qualitative reaction of Fe 3+ ions with thiocyanate ions SCN − is used. When Fe 3+ ions interact with SCN − anions, a mixture of bright red iron thiocyanate complexes 2+ , + , Fe(SCN) 3 , - is formed. The composition of the mixture (and hence the intensity of its color) depends on various factors, so this method is not applicable for the accurate qualitative determination of iron.

Another high-quality reagent for Fe 3+ ions is potassium hexacyanoferrate (II) K 4 (yellow blood salt). When Fe 3+ and 4− ions interact, a bright blue precipitate of Prussian blue precipitates:

Iron(VI) compounds

The oxidizing properties of ferrates are used to disinfect water.

Iron compounds VII and VIII

There are reports on the electrochemical preparation of iron(VIII) compounds. , , , however, there are no independent works confirming these results.

Application

Iron ore

Iron is one of the most used metals, accounting for up to 95% of the world's metallurgical production.

Iron is the main component of steels and cast irons - the most important structural materials.
Iron can be part of alloys based on other metals - for example, nickel.
Magnetic iron oxide (magnetite) is an important material in the manufacture of long-term computer memory devices: hard drives, floppy disks, etc.
Ultrafine magnetite powder is used in many black and white laser printers mixed with polymer granules as a toner. It uses both the black color of magnetite and its ability to adhere to a magnetized transfer roller.
The unique ferromagnetic properties of a number of iron-based alloys contribute to their widespread use in electrical engineering for the magnetic circuits of transformers and electric motors.
Iron (III) chloride (ferric chloride) is used in amateur radio practice for etching printed circuit boards.
Ferrous sulfate (iron sulfate) mixed with copper sulphate is used to control harmful fungi in gardening and construction.
Iron is used as an anode in iron-nickel batteries, iron-air batteries.
Aqueous solutions of chlorides of divalent and ferric iron, as well as its sulfates, are used as coagulants in the purification of natural and waste water in the water treatment of industrial enterprises.

The biological significance of iron

In living organisms, iron is an important trace element that catalyzes the processes of oxygen exchange (respiration). The body of an adult contains about 3.5 grams of iron (about 0.02%), of which 78% are the main active element of blood hemoglobin, the rest is part of the enzymes of other cells, catalyzing the processes of respiration in cells. Iron deficiency manifests itself as a disease of the body (chlorosis in plants and anemia in animals).

Normally, iron enters enzymes as a complex called heme. In particular, this complex is present in hemoglobin, the most important protein that ensures the transport of oxygen with blood to all organs of humans and animals. And it is he who stains the blood in a characteristic red color.

Iron complexes other than heme are found, for example, in the enzyme methane monooxygenase, which oxidizes methane to methanol, in the important enzyme ribonucleotide reductase, which is involved in DNA synthesis.

Inorganic iron compounds are found in some bacteria and are sometimes used by them to bind atmospheric nitrogen.

Iron enters the body of animals and humans with food (liver, meat, eggs, legumes, bread, cereals, beets are the richest in it). Interestingly, once spinach was erroneously included in this list (due to a typo in the analysis results - the “extra” zero after the decimal point was lost).

An excess dose of iron (200 mg or more) can be toxic. An overdose of iron depresses the antioxidant system of the body, so it is not recommended to use iron preparations for healthy people.

Notes

Chemical Encyclopedia: in 5 volumes / Ed.: Knunyants I. L. (chief editor). - M .: Soviet Encyclopedia, 1990. - T. 2. - S. 140. - 671 p. - 100,000 copies.
Karapetyants M. Kh., Drakin S. I. General and inorganic chemistry: Textbook for universities. - 4th ed., erased. - M.: Chemistry, 2000, ISBN 5-7245-1130-4, p. 529
M. Vasmer. Etymological dictionary of the Russian language. - Progress. - 1986. - T. 2. - S. 42-43.
Trubachev O. N. Slavic etymologies. // Questions of Slavic linguistics, No. 2, 1957.
Borys W. Slownik etymologiczny języka polskiego. - Krakow: Wydawnictwo Literackie. - 2005. - S. 753-754.
Walde A. Lateinisches etymologisches Wörterbuch. - Carl Winter's Universitätsbuchhandlung. - 1906. - S. 285.
Meye A. The main features of the Germanic group of languages. - URSS. - 2010. - S. 141.
Matasovic R. Etymological Dictionary of Proto-Celtic. - Brill. - 2009. - S. 172.
Mallory, J. P., Adams, D. Q. Encyclopedia of Indo-European Culture. - Fitzroy-Dearborn. - 1997. - P. 314.
"New Measurement of the 60 Fe Half-Life". Physical Review Letters 103 : 72502. DOI: 10.1103/PhysRevLett.103.072502 .
G. Audi, O. Bersillon, J. Blachot and A. H. Wapstra (2003). "The NUBASE evaluation of nuclear and decay properties". Nuclear Physics A 729 : 3–128. DOI:10.1016/j.nuclphysa.2003.11.001 .
Yu. M. Shirokov, N. P. Yudin. Nuclear physics. Moscow: Nauka, 1972. Chapter Nuclear space physics.
R. Ripan, I. Chetyanu. Inorganic chemistry // Chemistry of non-metals = Chimia metalelor. - Moscow: Mir, 1972. - T. 2. - S. 482-483. - 871 p.
Gold and Precious Metals
Metal science and heat treatment of steel. Ref. ed. In 3 volumes / Ed. M. L. Bershtein, A. G. Rakhshtadt. - 4th ed., revised. and additional T. 2. Fundamentals of heat treatment. In 2 books. Book. 1. M.: Metallurgiya, 1995. 336 p.
T. Takahashi & W.A. Bassett, "High-Pressure Polymorph of Iron," Science, Vol. 145 #3631, 31 Jul 1964, p 483-486.
Schilt A. Analytical Application of 1,10-phenantroline and Related Compounds. Oxford, Pergamon Press, 1969.
Lurie Yu. Yu. Handbook of analytical chemistry. M., Chemistry, 1989. S. 297.
Lurie Yu. Yu. Handbook of analytical chemistry. M., Chemistry, 1989, S. 315.
Brower G. (ed.) Guide to inorganic synthesis. v. 5. M., Mir, 1985. S. 1757-1757.
Remy G. Course of inorganic chemistry. vol. 2. M., Mir, 1966. S. 309.
Kiselev Yu. M., Kopelev N. S., Spitsyn V. I., Martynenko L. I. Octal iron // Dokl. Academy of Sciences of the USSR. 1987. T.292. pp.628-631
Perfil'ev Yu. D., Kopelev N. S., Kiselev Yu. Academy of Sciences of the USSR. 1987. T.296. C.1406-1409
Kopelev N.S., Kiselev Yu.M., Perfiliev Yu.D. Mossbauer spectroscopy of the oxocomplexes iron in higher oxidation states // J. Radioanal. Nucl. Chem. 1992. V.157. R.401-411.
"Norms of physiological needs for energy and nutrients for various groups of the population of the Russian Federation" MR 2.3.1.2432-08

Sources (to the History section)

G. G. Giorgadze."Text of Anitta" and some questions of the early history of the Hittites
R. M. Abramishvili. On the issue of the development of iron in the territory of Eastern Georgia, VGMG, XXII-B, 1961.
Khakhutayshvili D. A. On the history of ancient Colchian iron metallurgy. Questions of ancient history (Caucasian-Middle Eastern collection, issue 4). Tbilisi, 1973.
Herodotus."History", 1:28.
Homer. Iliad, Odyssey.
Virgil."Aeneid", 3:105.
Aristotle."On Incredible Rumors", II, 48. VDI, 1947, No. 2, p. 327.
Lomonosov M.V. The first foundations of metallurgy.

Links

Diseases caused by deficiency and excess of iron in the human body

Periodic system of chemical elements of D. I. Mendeleev




																						Fe

Iron in its pure form is a gray ductile metal that is easily machined. And yet, for humans, the Fe element is more practical in combination with carbon and other impurities that allow the formation of metal alloys - steels and cast irons. 95% - that is how much of all metal products produced on the planet contain iron as the main element.

Iron: history

The first iron products made by man are dated by scientists to the 4th millennium BC. e., and studies have shown that meteoric iron was used for their production, which is characterized by a 5-30% nickel content. Interestingly, until mankind mastered the extraction of Fe by smelting it, iron was valued more than gold. This was explained by the fact that stronger and more reliable steel was much more suitable for the manufacture of tools and weapons than copper and bronze.

The ancient Romans learned how to make the first cast iron: their furnaces could raise the temperature of the ore to 1400 ° C, while 1100-1200 ° C was enough for cast iron. Subsequently, they also received pure steel, the melting point of which, as you know, is 1535 degrees Celsius. Celsius.

Chemical properties of Fe

What does iron interact with? Iron interacts with oxygen, which is accompanied by the formation of oxides; with water in the presence of oxygen; with sulfuric and hydrochloric acids:

3Fe + 2O 2 \u003d Fe 3 O 4
4Fe + 3O 2 + 6H 2 O \u003d 4Fe (OH) 3
Fe + H 2 SO 4 \u003d FeSO 4 + H 2
Fe + 2HCl \u003d FeCl 2 + H 2

Also, iron reacts to alkalis only if they are melts of strong oxidizing agents. Iron does not react with oxidizing agents at ordinary temperature, but always begins to react when it is raised.

The use of iron in construction

The use of iron by the construction industry today cannot be overestimated, because metal structures are the basis of absolutely any modern structure. In this area, Fe is used in the composition of conventional steels, cast iron and wrought iron. This element is everywhere, from critical structures to anchor bolts and nails.

The construction of building structures made of steel is much cheaper, besides, here we can talk about higher rates of construction. This markedly increases the use of iron in construction, while the industry itself masters the use of new, more efficient and reliable alloys based on Fe.

The use of iron in industry

The use of iron and its alloys - cast iron and steel - is the basis of modern machine, machine tool, aircraft, instrument making and the manufacture of other equipment. Thanks to cyanides and Fe oxides, the paint and varnish industry functions, iron sulfates are used in water treatment. Heavy industry is completely unthinkable without the use of alloys based on Fe + C. In a word, iron is an irreplaceable, but at the same time accessible and relatively inexpensive metal, which in the composition of alloys has an almost unlimited scope.

The use of iron in medicine

It is known that each adult contains up to 4 grams of iron. This element is extremely important for the functioning of the body, in particular, for the health of the circulatory system (hemoglobin in red blood cells). There are many iron-based drugs that allow you to increase the content of Fe in order to avoid the development of iron deficiency anemia.

Iron- metal, the use of which in industry and everyday life has practically no boundaries. The share of iron in the world production of metals is about 95%. Its use, like any other material, is due to certain properties.

Iron has played a huge role in the development of human civilization. Primitive man began to use iron tools several millennia BC. Then, the only source of this metal were meteorites that fell to Earth, which contained fairly pure iron. This gave rise to legends among many peoples about the heavenly origin of iron.

In the middle of the II millennium BC. In Egypt, the extraction of iron from iron ores was mastered. It is believed that this marked the beginning of the Iron Age in the history of mankind, which replaced the Stone and Bronze Ages. However, already 3-4 thousand years ago, the inhabitants of the Northern Black Sea region - the Cimmerians - smelted iron from swamp ore.

Iron has not lost its significance to this day. It is the most important metal of modern technology. Due to its low strength, iron is practically not used in its pure form. However, in everyday life, steel or cast iron products are often called "iron". After all, important structural materials - steels and cast irons - are alloys of iron with carbon. They make a wide variety of items.

The octagonal pedestal of the monument to Prince Vladimir is built of brick and lined with cast iron.

The prototype of the gigantic structure of the Atomium in Brussels was the model of the crystal lattice of iron. After the reconstruction, the Atomium is again open to the public. The original cover of each ball with an area of 240 m 2 was made of 720 triangular aluminum plates. Now they have been replaced by 48 stainless steel plates.

In addition, iron can be a component of alloys based on other metals, such as nickel. Magnetic alloys also contain iron.

Iron-based materials are created that can withstand high and low temperatures, vacuum and high pressures. They successfully resist aggressive environments, alternating voltage, radioactive radiation, etc.

The production of iron and its alloys is constantly growing. These materials are universal, technologically advanced, available and in bulk - cheap. The raw material base of iron is quite large. Already explored reserves of iron ore will last at least two centuries. Therefore, iron will long remain the "foundation" of civilization.

Iron has long been used as an artistic material in Egypt, Mesopotamia, and India. Since the Middle Ages, numerous highly artistic items made of iron alloys have been preserved. Modern artists also widely use iron alloys. material from the site

Among the many artistic products, one cannot leave out of sight the "Mertsalov's Palm" - a work of art by Ukrainian masters. It was forged by Aleksey Mertsalov at the Yuzovsky Metallurgical Plant in 1886. She was recognized as worthy of the Grand Prix of the All-Russian Industrial and Art Exhibition in Nizhny Novgorod. In 1900, Mertsalov's Palm, as part of the exposition of the Yuzovsky Plant, received the highest award at the World Exhibition in Paris.

And in the XXI century. it is difficult to find an industry where iron is not used. Its importance has not diminished with the transition of many metal functions to synthetic materials created by the chemical industry.

Lesson Objectives:

to form an idea of the physical and chemical properties of iron, depending on the degree of oxidation it exhibits and the nature of the oxidizing agent;
develop the theoretical thinking of students and their ability to predict the properties of matter, based on knowledge of its structure;
develop conceptual thinking of such operations as analysis, comparison, generalization, systematization;
develop such qualities of thinking as objectivity, conciseness and clarity, self-control and activity.

Lesson objectives:

update students' knowledge on the topic: "The structure of the atom";
organize the collective work of students from setting a learning task to the final result (draw up a reference diagram for the lesson);
summarize the material on the topic: “Metals” and consider the properties of iron and its application;
organize independent research work in pairs to study the chemical properties of iron;
organize mutual control of students in the classroom.

Lesson type: learning new material.

Reagents and equipment:

iron (powder, plate, paper clip),
sulfur,
hydrochloric acid,
copper(II) sulfate,
iron crystal lattice,
game posters,
magnet,
a selection of illustrations on the topic,
test tubes,
spirit lamp,
matches,
spoon for burning combustible substances,
geographic Maps.

Lesson structure

Introductory part.
Learning new material.
Homework message.
Consolidation of the studied material.

During the classes

1. Introduction

Organizing time.

Checking for students.

The topic of the lesson. Write the topic on the board and in students' notebooks.

2. Learning new material

What do you think the topic of our lesson today will be?

1. The appearance of iron in human civilization marked the beginning of the Iron Age.

The famous damask steel (or damask steel) was made in the East back in the time of Aristotle (4th century BC). But the technology of its manufacture was kept secret for many centuries.

I dreamed of a different sadness
About gray Damascus steel.
I saw the steel temper
As one of the young slaves
Chose, fed him,
So that the flesh of his strength was recruited.
Waiting for the due date
And then a hot blade
Immersed in muscular flesh
They took out the finished blade.
Stronger than steel, did not see the East,
Stronger than steel and bitterer than sorrow.

(Demonstration of drawings.)

Iron - silver gray metal	Iron - silver gray metal
These nails are made of iron	Steel is used in the automotive industry
Steel is used to make medical instruments	Steel is used to make locomotives
	All metals are susceptible to corrosion
All metals are susceptible to corrosion

2. The position of iron in PSCHEM.

We find out the position of iron in the PSCM, the charge of the nucleus and the distribution of electrons in the atom.

3. Physical properties of iron.

What physical properties of iron do you know?

4. Chemical properties of iron.

Based on the knowledge about the chemical properties of metals, what do you think the chemical properties of iron will be?

Demonstration of experiences.

The interaction of iron with sulfur.

Practical work.

The interaction of iron with hydrochloric acid.
Interaction of iron with copper (II) sulfate.

5. The use of iron.

Conversation on:

- How do you think up, what is the distribution of iron in nature?

Iron ores are quite widespread on Earth. The names of the mountains in the Urals speak for themselves: High, Magnetic, Iron. Agricultural chemists find iron compounds in soils.

In what form does iron occur in nature?

What is the role of iron in human and plant life?

So from the same reason - the presence of iron in juices and tissues - the leaves of plants turn green cheerfully and the cheeks of a person blush brightly.

3. Post home stuff

14, ex. No. 6, 8, 9 (according to the workbook for the textbook by O.S Gabrielyan “Chemistry 9”, 2003).

4. Consolidation of the studied material

Using the reference diagram written on the blackboard, conclude: what is iron and what are its properties?
Graphic dictation (prepare in advance leaflets with a drawn straight line, divided into 8 segments and numbered according to the questions of the dictation. Mark with a hut “^” on the segment the number of the position that is considered correct).

Option 1.

Iron is an active alkali metal.
Iron is easily forged.
Iron is part of the bronze alloy.
The outer energy level of an iron atom has 2 electrons.
Iron interacts with dilute acids.
With halogens it forms halides with an oxidation state of +2.
Iron does not interact with oxygen.
Iron can be obtained by electrolysis of its salt melt.


1	2	3	4	5	6	7	8

Option 2.

Iron is a silver-white metal.
Iron does not have the ability to be magnetized.
Iron atoms exhibit oxidizing properties.
The outer energy level of an iron atom has 1 electron.
Iron displaces copper from solutions of its salts.
With halogens, it forms compounds with an oxidation state of +3.
With a solution of sulfuric acid forms iron sulfate (III).
Iron does not corrode.


1	2	3	4	5	6	7	8

After completing the assignment, students change their work and check it (the answers to the work are posted on the board, or show through the projector).

Mark criteria:

"5" - 0 errors,
“4” - 1-2 errors,
"3" - 3-4 errors,
"2" - 5 or more errors.

Used Books

Gabrielyan O.S. Chemistry grade 9. – M.: Bustard, 2001.
Gabrielyan O.S. The book for the teacher. – M.: Bustard, 2002.
Gabrielyan O.S. Chemistry grade 9. Workbook. – M.: Bustard, 2003.
Education industry. Digest of articles. Issue 3. - M .: MGIU, 2002.
Malyshkina V. Entertaining chemistry. - St. Petersburg, "Trigon", 2001.
Program-methodical materials. Chemistry 8-11 grades. – M.: Bustard, 2001.
Stepin B.D., Alikberova L.Yu. Chemistry book for home reading. – M.: Chemistry, 1995.
I'm going to chemistry class. The book for the teacher. – M.: “First of September”, 2000.

Applications

Do you know that?

Hematite

The name of the mineral comes from the Greek deta- blood, which is associated with the cherry or wax-red color of the powder of this mineral.

Chemical and physical properties of iron

The reaction of iron with oxygen

Production of iron oxides

Chemical properties of iron

Obtaining and using iron

1. Introduction

2. Learning new material

3. Post home stuff

4. Consolidation of the studied material

Used Books

Applications

Do you know that?

Hematite

Magnetite

Pyrite is a mineral similar to fire.

Story

origin of name

isotopes

Geochemistry of iron

Geochemical properties of iron

iron minerals

Main deposits

Receipt

Physical properties

Chemical properties

Characteristic oxidation states

Properties of a simple substance

Iron(II) compounds

Iron(III) compounds

Iron(VI) compounds

Iron compounds VII and VIII

Application

The biological significance of iron

Notes

Sources (to the History section)

see also

Links

Iron: history

Chemical properties of Fe

The use of iron in construction

The use of iron in industry

The use of iron in medicine

1. Introduction

2. Learning new material

3. Post home stuff

4. Consolidation of the studied material

Used Books

Applications

Do you know that?

Hematite

Magnetite

Pyrite is a mineral similar to fire.

Functions of cell organelles

Algorithm for writing an essay on social studies

Chernobyl in the memoirs of eyewitnesses Chernobyl scary stories