The iron eighth element of the fourth period in the Mendeleev table. Its number in the table (also called atomic) 26, which corresponds to the number of protons in the kernel and electrons in the electron shell. It is indicated by the first two letters of its Latin equivalent - FE (Ferrum - read as "Ferrum"). Iron - the second prevalence element in earth Kore, percentage - 4.65% (the most common - aluminum, Al). In native form, this metal is rare quite rarely, more often it is extracted from a mixed ore with nickel.

In contact with

What is the nature of this connection? The iron as an atom consists of a metal crystal lattice, due to which the solidness of the compounds containing this element is ensured, and molecular resistance. It is in this connection that this metal is typical solid In contrast, for example, mercury.

Iron as a simple substance - Silver metal metal typical for this group of elements properties: Purpure, metal shine and plasticity. In addition, iron has a high reaction activity. The last property is indicated by the fact that iron is very quickly subject to corrosion in the presence of high temperature and appropriate humidity. In pure oxygen, this metal is well lit, and if you look at very small particles, they will not be easy to burn, but to be self-turn.

We call the iron without pure metal, but its alloys containing carbon ©, for example, steel (<2,14% C) и чугун (>2.14% c). Also important industrial significance have alloys in which alloying metals (nickel, manganese, chromium and others) are added, due to them, steel becomes stainless, i.e. doped. Thus, based on this, it becomes clear which extensive industrial use has this metal.

Feature Fe.

Chemical properties of iron

Consider in more detail the features of this element.

Properties of a simple substance

• Oxidation in air at high humidity (corrosion process):

4Fe + 3O2 + 6H2O \u003d 4Fe (OH) 3 - hydroxide (hydroxide) iron (III)

• The combustion of iron wire in oxygen with the formation of mixed oxide (it is in it an element and with a degree of oxidation +2, and with a degree of oxidation +3):

3Fe + 2O2 \u003d Fe3O4 (iron scale). The reaction is possible when heated to 160 ⁰C.

• Interaction with water at high temperature (600-700 ⁰C):

3Fe + 4H2O \u003d Fe3O4 + 4H2

• Reactions with non-metals:

a) Reaction with halogens (important! With this interaction, the degree of oxidation of the element is acquired by +3)

2fe + 3Cl2 \u003d 2FeCl3 - Trohulant Iron chloride

b) reaction with gray (important! With this interaction, the element has a degree of oxidation +2)

Iron sulphide (III) - Fe2S3 can be obtained during another reaction:

Fe2O3 + 3H2S \u003d FE2S3 + 3H2O

c) formation of pyrite

Fe + 2s \u003d Fes2 - Pyrite. Pay attention to the degree of oxidation of the elements constituting this compound: FE (+2), S (-1).

• The interaction with salts of metals standing in an electrochemical row of metal activity to the right of Fe:

Fe + Cucl2 \u003d FECL2 + CU - iron chloride (II)

• Interaction with dilute acids (for example, hydrochloric and sulfur):

Fe + HBr \u003d FeBr2 + H2

Fe + HCl \u003d FECL2 + H2

Note that in these reaction it turns out iron with a degree of oxidation +2.

• In undiluted acids, which are the strongest oxidizers, the reaction is possible only when heated, metal is passivated in cold acids:

Fe + H2SO4 (concentrated) \u003d Fe2 (SO4) 3 + 3SO2 + 6H2O

Fe + 6hnO3 \u003d Fe (NO3) 3 + 3NO2 + 3H2O

• Amphoteric properties of iron are manifested only when interacting with concentrated alkalis:

Fe + 2KOH + 2H2O \u003d K2 + H2 - tetrahydroxyferrat (II) Potassium falls into a sediment.

Cast iron production process in a blast furnace

• Firing and subsequent decomposition of sulfide and carbonate ores (metal oxide release):

FES2 -\u003e Fe2O3 (O2, 850 ⁰C, -SO2). This reaction is also the first step in the industrial synthesis of sulfuric acid.

FECO3 -\u003e Fe2O3 (O2, 550-600 ⁰C, -CO2).

• Burning coke (in excess):

C (coke) + O2 (WIT.) -\u003e CO2 (600-700 ⁰C)

CO2 + C (Coke) -\u003e 2CO (750-1000 ⁰C)

• Rud restoration containing oxide carbon monoxide:

Fe2O3 -\u003e FE3O4 (CO, -CO2)

Fe3O4 -\u003e Feo (CO, -CO2)

Feo -\u003e Fe (CO, -CO2)

• Iron carburization (up to 6.7%) and cast iron melting (t⁰loves - 1145 ⁰C)

Fe (hard) + s (coke) -\u003e cast iron. Reaction temperature - 900-1200 ⁰C.

The cast iron is always present in the form of grain cementite (Fe2C) and graphite.

Feature Compounds containing Fe

Let's study the features of each connection separately.

Fe3O4.

Mixed or double iron oxide, having in its composition an element with an oxidation degree of both +2 and +3. Also FE3O4 is called iron Scale. This connection is steady tolerate high temperatures. Does not react with water, water vapor. Subjected to decomposition with mineral acids. It may be restored by hydrogen or iron at high temperature. As you could understand the above information, is an intermediate product in the chain of the reaction of industrial production of cast iron.

Directly iron abaline is used in the production of paints on mineral base, color cement and ceramics products. FE3O4 is what is obtained in black and binding steel. A mixed oxide is obtained by combustion of iron in air (the reaction is given above). Ore containing oxides is magnetite.

Fe2O3.

Iron oxide (III), trivial name - hematite, Red-brown connection. Resistant to high temperatures. In its pure form, it is not formed when iron oxidation oxygen. Does not react with water, forms hydrates falling into a precipitate. Poor reacts with diluted alkalis and acids. It can be melted with oxides of other metals, forming spinels - double oxides.

Red Zheleznyak is used as a raw material with an industrial production of cast iron by a domain way. Also speeds up the reaction, that is, is a catalyst in the ammonia industry. It is used in the same areas as the iron scale. Plus, it was used as a carrier of sound and pictures on magnetic ribbons.

Feoh2.

Iron hydroxide (II)The compound with both acidic and basic properties prevail the latter, that is, is amphoteric. The white substance that is rapidly oxidized in air, "drill" to iron hydroxide (III). We are susceptible to decay when exposed to temperature. It reaches the reaction and with weak solutions of acids, and with alkalis. In water will not soluble. The reaction acts as a reducing agent. It is an intermediate product in the corrosion reaction.

Detection of FE2 + and Fe3 + ions ("high-quality" reactions)

FE2 + and FE3 + ion recognition in aqueous solutions They are produced using complex complex compounds - K3, red blood salt, and k4, yellow blood salt, respectively. In both reactions, a saturated blue precipitate is dropped with the same quantitative composition, but by different iron position with valence +2 and +3. This precipitate is also often called Berlin Azure or Turnbull Blue.

Reaction recorded in ion form

Fe2 ++ k ++ 3-  k + 1fe + 2

Fe3 ++ K ++ 4-  K + 1FE + 3

Good reagent for detecting Fe3 + - Toyocianate ion (NCS-)

Fe3 ++ NCS-  3- - These compounds have bright red ("bloody") color.

This reagent, for example, potassium thiocyanate (formula - Kncs), makes it possible to determine even a negligible concentration of iron in solutions. So, it is capable of studying the tap water to determine whether the pipes did not rust.

Length Converter Length Converter Mass Converter Volume Resume Products and Food Converter Square Converter Volume and Units Measurement In Culinary Recipes Temperature Converter Converter Pressure, Mechanical Voltage, Module Jung Converter Energy and Operation Converter Power Converter Power Converter Time Converter Linear Speed \u200b\u200bFlat Angle Converter Heat Efficiency and Fuel Engineering Converter Numbers in Different Systems Systems Converter Units Measurement Quantity Currency Currency Dimensions Women's Clothing Sizes Men's Clothing And Shoe Corner Speed \u200b\u200bConverter and Rotation Converter Speed \u200b\u200bConverter Corner Acceleration Converter Density Converter Specific Specification Converter Moment Inertia Moment Moment Converter Rotary Converter Converter Specific heat combustion (by weight) Energy density converter and specific heat combustion (by volume) Temperature converter Converter coefficient Heat Expansion Converter Thermal Resistance Converter Specific Conductivity Converter Specific Steel Converter Energy Exposure and Power heat radiation Heat flux density converter heat transfer coefficient converter voluminous consumption mass flow converter Molar consumption converter mass flow converter mass converter molar concentration converter mass concentration in solution dynamic viscosity converter converter converter converter converter surface tension Parry Permiety Converter Water Pair Density Converter Sound Sound Converter Microphones Sound Pressure Level Converter (SPL) Sound Pressure Level Converter With Reference Pressure Converter Light Converter Light Converter Converter Permissions In Computer Grade Frequency Converter and Wave Frequency Converter Optical power in diopters and focal length optical power in diopters and zooming lenses (×) electrical charge converter linear charge converter charging surface density converter charging density charge electric current converter line reinforcement current converter current electric field power converter electrostatic potential converter electrical converter Resistance Specific Electrical Resistance Converter Electrical Conductivity Converter Specific Electrical Converter Electrical Capacity Inductance Converter Converter American Caliber Wires Levels in DBM (DBM or DBMWT), DBV (DBV), Watts, etc. Units Converter Magnetotive Force Converter Tension magnetic field Converter magnetic flux Magnetic induction converter radiation. Power converter absorbed dose of ionizing radiation radioactivity. Radioactive decay converter radiation. Converter exposure dose radiation. Converter of absorbed dose converter decimal consoles data transmission converter units typography and image processing converter units measurement of timber volume calculation of molar mass Periodic system chemical elements D. I. Mendeleev

Chemical formula

FE 2 molar mass (SO 4) 3, iron sulfate (III) 399.8778 g / mol

55,845 · 2 + (32.065 + 15,9994 · 4) · 3

Mass shares of elements in connection

Using the molar mass calculator

• Chemical formulas need to be administered with the register
• Indices are entered as ordinary numbers
• The point on the midline (multiplication sign), used, for example, in crystalline formulas, is replaced by a normal point.
• Example: Instead of Cuso₄ · 5H₂o in the converter for ease of entry, you are writing Cuso4.5H2O.

Molar Mass Calculator

Mole

All substances consist of atoms and molecules. In chemistry, it is important to accurately measure the mass of substances entering into the reaction and resulting from it. By definition, Mol is a unit of the amount of substance in C. One mol contains exactly 6.02214076 × 10 ²³ of elementary particles. This value is numerically equal to the Avogadro Constant N A, if expressed in units of Mol⁻⁻ and is called the Nogadro number. Number of substance (symbol n.) Systems is a measure of the number of structural elements. Structural element There may be an atom, molecule, ion, electron or any particle or particle group.

Permanent Avogadro N a \u003d 6.02214076 × 10²³ Mol⁻⁻. Number of Avogadro - 6.02214076 × 10²³.

In other words, mol is the amount of a substance equal to the mass of the sum of atomic masses of atoms and the substance molecules multiplied by the Avogadro. The unit of the amount of substance mole is one of the seven major units of the SI system and is indicated by mol. Since the name of the unit and its conditional designation coincide, it should be noted that the conditional designation is not inclined, in contrast to the name of the unit that can be inclined by regular rules Russian language. One mole of pure carbon-12 is exactly 12 g.

Molar mass

Molar mass - physical property Substances defined as the ratio of the mass of this substance to the amount of substance in moles. Speaking otherwise, this is the mass of one praying matter. In the system system of the molar mass is kilogram / mol (kg / mol). However, chemists are accustomed to enjoy a more convenient unit of g / mol.

molar mass \u003d g / mol

Molar mass of elements and connections

Compounds - substances consisting of various atoms that are chemically related to each other. For example, the following substances that can be found in the kitchen in any hostess are chemical compounds:

• salt (sodium chloride) NaCl
• sugar (sucrose) C₁₂H₂₂O₁₁
• vinegar (acetic acid solution) CH₃COOH

The molar mass of chemical elements in grams on the mole numerically coincides with the mass of the atoms of the element, expressed in atomic units of mass (or Dalton). The molar mass of the compounds is equal to the sum of the molar masses of the elements, of which the compound consists, taking into account the number of atoms in the compound. For example, the molar mass of water (H₂O) is approximately equal to 1 × 2 + 16 \u003d 18 g / mol.

Molecular mass

The molecular weight (the old name is molecular weight) is the mass of the molecule, calculated as the sum of the masses of each atom, which is part of the molecule multiplied by the number of atoms in this molecule. Molecular weight is dimensionless physical quantity, numerically equal molar mass. That is, the molecular weight differs from molar mass dimension. Despite the fact that the molecular weight is a dimensionless value, it still has a value called the atomic unit of mass (A.E.M.) or Dalton (yes), and approximately equal mass of one proton or neutron. The atomic unit of mass is also numerically equal to 1 g / mol.

Calculation of molar mass

The molar mass is calculated so:

• the atomic masses of the elements on the Mendeleev table are determined;
• determine the number of atoms of each element in the compound formula;
• determine the molar mass, folding the atomic masses of the elements included in the connection multiplied by their number.

For example, we calculate the molar mass of acetic acid

It consists of:

• two carbon atoms
• four hydrogen atoms
• two oxygen atoms

• carbon C \u003d 2 × 12,0107 g / mol \u003d 24,0214 g / mol
• hydrogen H \u003d 4 × 1,00794 g / mol \u003d 4,03176 g / mol
• oxygen O \u003d 2 × 15,9994 g / mol \u003d 31,9988 g / mol
• molar mass \u003d 24,0214 + 4,03176 + 31,9988 \u003d 60,05196 g / mol

Our calculator performs such a calculation. You can enter the formula of acetic acid into it and check what happens.

Do you find it difficult to translate units of measure from one language to another? Colleagues are ready to help you. Publish a question in tcterms And within a few minutes you will receive an answer.

The human body contains about 5 g of iron, most of it (70%) is part of the hemoglobin of blood.

Physical properties

In the free state of iron - silver-white metal with a grayish tint. Pure iron plastic, has ferromagnetic properties. In practice, iron alloys are usually used and steel.

Fe - the most important and most common element of nine D-metals by the side subgroup Group VIII. Together with cobalt and nickel forms "Iron family".

When forming compounds with other elements, 2 or 3 electrons (B \u003d II, III) uses 2 or 3.

Iron, like almost all D-elements of the VIII group, does not show the highest valence equal to the group number. Its maximum valence reaches VI and manifests itself extremely rare.

The most characteristic of the compounds in which FE atoms are in oxidation degrees +2 and +3.

Methods for obtaining iron

1. Technical iron (in alloy with carbon and other impurities) are obtained by carboermic recovery natural connections according to the scheme:

Recovery occurs gradually, in 3 stages:

1) 3Fe 2 O 3 + CO \u003d 2FE 3 O 4 + CO 2

2) FE 3 O 4 + CO \u003d 3FEO + CO 2

3) FEO + CO \u003d Fe + CO 2

The cast iron formed as a result of this process contains more than 2% of carbon. In the future, steel are obtained from cast iron, iron alloys containing less than 1.5% of carbon.

2. Very clean iron get one way:

a) FE pentarbonyl decomposition

Fe (CO) 5 \u003d Fe + 5Co

b) Hydrogen Recovery Pure Feo

Feo + H 2 \u003d Fe + H 2 O

c) Electrolysis of aqueous solutions of FE salts +2

FEC 2 O 4 \u003d Fe + 2SO 2

iron oxalate (II)

Chemical properties

Fe is a metal of medium activity, exhibits common properties characteristic of metals.

A unique feature is the ability to "rust" in wet air:

In the absence of moisture with dry air, iron begins to react noticeably only at T\u003e 150 ° C; When calculating, "Iron Okalina" Fe 3 O 4 is formed:

3Fe + 2O 2 \u003d Fe 3 O 4

In water in the absence of oxygen, iron is not dissolved. At very high temperature FE reacts with water vapor, hung hydrogen from water molecules:

3 Fe + 4N 2 O (g) \u003d 4H 2

The rusting process in its mechanism is electrochemical corrosion. Rust product is presented in a simplified form. In fact, a loose layer of mixtures of oxides and hydroxides of variable composition is formed. Unlike the film AL 2 O 3, this layer does not protect the iron from further destruction.

Types of corrosion

Corrosion Iron Protection

1. Interaction with halogens and gray at high temperatures.

2fe + 3Cl 2 \u003d 2FeCl 3

2fe + 3F 2 \u003d 2FEF 3

Fe + i 2 \u003d Fei 2

Compounds are formed in which the ion type of communication prevails.

2. Interaction with phosphorus, carbon, silicon (C N 2 and H 2 Iron is not directly connected, but dissolves them).

Fe + P \u003d Fe x P y

Fe + C \u003d Fe x C y

Fe + Si \u003d Fe x Si Y

The substances of the variable composition are formed, T to. Bertollides (in the compounds prevailing the covalent nature of communication)

3. Interaction with "non-oxidizing" acids (HCl, H 2 SO 4 sample.)

Fe 0 + 2n + → Fe 2+ + H 2

Since FE is located in a number of activity of the left of the hydrogen (E ° FE / Fe 2+ \u003d -0.44B), it can be able to exhibit H 2 from ordinary acids.

Fe + 2HCl \u003d FECL 2 + H 2

Fe + H 2 SO 4 \u003d FESO 4 + H 2

4. Interaction with "oxidizing" acids (HNO 3, H 2 SO 4 conc.)

Fe 0 - 3e - → Fe 3+

The concentrated HNO 3 and H 2 SO 4 "passivate" the iron, so at normal temperature the metal does not dissolve in them. With strong heating, slow dissolution occurs (without highlighting H 2).

In RSC. HNO 3 iron dissolves, enters the solution in the form of Fe 3+ cations and an acid anion is restored to NO *:

Fe + 4hno 3 \u003d Fe (NO 3) 3 + No + 2n 2 O

Very well dissolved in a mixture of NSL and HNO 3

5. Attitude to alkalis

In aqueous solutions, FE alkalis does not dissolve. With molten alkalis, it reacts only at very high temperatures.

6. Interaction with salts of less active metals

Fe + Cuso 4 \u003d Feso 4 + Cu

Fe 0 + Cu 2+ \u003d Fe 2+ + Cu 0

7. Interaction with gaseous carbon monoxide (T \u003d 200 ° C, p)

Fe (Powder) + 5Co (D) \u003d Fe 0 (CO) 5 Pentarbonyl Iron

FE (III) compounds

Fe 2 O 3 - iron (III) oxide.

Red-brown powder, n. R. In H 2 O. In Nature - "Red Zheleznyak".

Methods for obtaining:

1) iron hydroxide decomposition (III)

2Fe (OH) 3 \u003d Fe 2 O 3 + 3H 2 O

2) firing pyrite

4fes 2 + 11o 2 \u003d 8SO 2 + 2FE 2 O 3

3) decomposition of nitrate

Chemical properties

Fe 2 O 3 is the main oxide with signs of amphoterity.

I. The main properties are manifested in the ability to react with acids:

Fe 2 O 3 + 6N + \u003d 2FE 3+ + ZN 2 O

Fe 2 O 3 + 6HCI \u003d 2FECI 3 + 3H 2 O

Fe 2 O 3 + 6HNO 3 \u003d 2FE (NO 3) 3 + 3H 2 O

II. Weakness properties. In aqueous solutions, FE 2 O 3 alkalis is not dissolved, but when fusing with solid oxides, alkalis and carbonates, ferrite formation occurs:

Fe 2 O 3 + SAO \u003d CA (Feo 2) 2

Fe 2 O 3 + 2NAOH \u003d 2NAFEO 2 + H 2 O

Fe 2 O 3 + Mgco 3 \u003d Mg (FeO 2) 2 + CO 2

III. Fe 2 O 3 - Fine raw materials for iron in metallurgy:

Fe 2 O 3 + ZS \u003d 2FE + SSO or Fe 2 O 3 + SSO \u003d 2FE + ZO 2

Fe (OH) 3 - iron hydroxide (III)

Methods for obtaining:

Obtained under the action of alkalisks for soluble salts Fe 3+:

FECL 3 + 3NAOH \u003d FE (OH) 3 + 3NACL

At the time of receipt of Fe (OH) 3 - red-brown mucous amorphic precipitate.

Fe (III) hydroxide is also formed when oxidation on wet air FE and FE (OH) 2:

4Fe + 6N 2 O + 3O 2 \u003d 4Fe (OH) 3

4Fe (OH) 2 + 2N 2 O + O 2 \u003d 4FE (OH) 3

FE (III) hydroxide is a final product of FE 3+ salts hydrolysis.

Chemical properties

Fe (OH) 3 is a very weak base (much weaker than FE (OH) 2). Shows noticeable acid properties. Thus, FE (OH) 3 has amphoteric character:

1) reactions with acids proceed easily:

2) Fresh precipitate Fe (OH) 3 dissolves in hot conc. Con or NaOH solutions to form hydroxamplexes:

Fe (OH) 3 + 3Con \u003d K 3

In an alkaline solution Fe (OH) 3 can be oxidized to ferrates (salts not selected in the free state of iron acid H 2 FeO 4):

2fe (OH) 3 + 10Cone + 3Br 2 \u003d 2K 2 FeO 4 + 6kvr + 8H 2 O

FE 3+ salts

Most practically important are: Fe 2 (SO 4) 3, FECL 3, FE (NO 3) 3, Fe (SCN) 3, K 3 4- yellow blood salt \u003d Fe 4 3 Berlin Azure (dark blue sediment)

b) Fe 3+ + 3Scn - \u003d Fe (SCN) 3 Rodanide Fe (III) (PR Blood-Red)

Iron compounds (II)

The compounds of iron with the degree of oxidation of iron +2 is small-resistant and easily oxidized to the iron derivatives (III).

Fe 2 O 3 + CO \u003d 2FEO + CO 2.

Iron hydroxide (II) Fe (OH) 2in freshly lined form, it has a grayish-green color, it does not dissolve in water, at temperatures above 150 ° C decomposes, quickly darkens due to oxidation:

4Fe (OH) 2 + O 2 + 2H 2 O \u003d 4FE (OH) 3.

Exhibits low-voltage amphoteric properties with the predominance of basic, easily reacts with non-oxidizing acids:

Fe (OH) 2 + 2HCl \u003d FECL 2 + 2H 2 O.

Interacting with concentrated alkali solutions when heated to the formation of tetrahydroxerrate (II):

Fe (OH) 2 + 2NAOH \u003d Na 2.

Exhibits reducing properties, when interacting with nitric or concentrated sulfuric acid, iron (III) salts are formed:

2Fe (OH) 2 + 4H 2 SO 4 \u003d Fe 2 (SO 4) 3 + SO 2 + 6H 2 O.

It turns out in the interaction of iron (II) salts with alkali mortar in the absence of air oxygen:

FESO 4 + 2NAOH \u003d FE (OH) 2 + Na 2 SO 4.

Salts of iron (II).Iron (II) forms salts with almost all anions. Typically, salts are crystallized in the form of green crystalline hydrogen: FE (NO 3) 2 · 6H 2 O, FESO 4 · 7H 2 O, FeSO 2 · 6H 2 O, (NH 4) 2 Fe (SO 4) 2 · 6H 2 O (salt Mora) and others. Salts solutions have a pale green color and, due to hydrolysis, a sour Wednesday:

Fe 2+ + H 2 O \u003d Feoh + + H +.

Exhibit all the properties of salts.

When standing in air is slowly oxidized by dissolved oxygen to iron salts (III):

4FeCl 2 + O 2 + 2H 2 O \u003d 4Feohcl 2.

High-quality reaction to Fe 2+ cation - interaction with potassium hexaciatorrate (III) (red blood saline):

FESO 4 + K 3 \u003d KFE ↓ + K 2 SO 4

Fe 2+ + K + + 3- \u003d KFE ↓

as a result of the reaction, a blue precipitate is formed - hexaciaranrat (II) iron (III) - potassium.

The degree of oxidation is +3 characteristic of iron.

Iron oxide (III) Fe 2 O 3 -the brown substance exists in three polymorphic modifications.

Exhibits low-generated amphoteric properties with the predominance of the main. Easily reacts with acids:

Fe 2 O 3 + 6HCl \u003d 2FeCl 3 + 3H 2 O.

With alkalis solutions, it does not respond, but when fusing it forms ferrites:

Fe 2 O 3 + 2NAOH \u003d 2NAFEO 2 + H 2 O.

Shows oxidative and rehabilitation properties. When heated is restored by hydrogen or carbon oxide (II), showing oxidative properties:

Fe 2 O 3 + H 2 \u003d 2Feo + H 2 O,

Fe 2 O 3 + CO \u003d 2FEO + CO 2.

In the presence of strong oxidizing agents, the alkaline medium shows the rehabilitation properties and is oxidized to the iron derivatives (VI):

Fe 2 O 3 + 3KNO 3 + 4KOH \u003d 2K 2 FeO 4 + 3Kno 2 + 2H 2 O.

At temperatures above 1400 ° C decomposes:

6Fe 2 O 3 \u003d 4Fe 3 O 4 + O 2.

It turns out with thermal decomposition of iron hydroxide (III):

2Fe (OH) 3 \u003d Fe 2 O 3 + 3H 2 O

or oxidation of pyrite:

4FES 2 + 11O 2 \u003d 2FE 2 O 3 + 8SO 2.

FECL 3 + 3KCNS \u003d FE (CNS) 3 + 3KCL,

Iron - element of a side subgroup of the eighth group of the fourth period periodic system Chemical elements D. I. Mendeleev with atomic number 26. is denoted by the FE symbol (lat. ferrum). One of the most common metals in the earth's crust (second place after aluminum). Metal medium activity, reducing agent.

Basic degrees of oxidation - +2, +3

A simple substance of iron - a dowel metal of silver-white color with a high chemical reactivity: iron quickly corps at high temperatures or with high humidity in air. In pure oxygen, iron is lit, and in a fine state self-turning and in air.

Chemical properties of a simple substance - iron:

Rust and combustion in oxygen

1) The air is easily oxidized in the air in the presence of moisture (rust):

4Fe + 3O 2 + 6H 2 O → 4Fe (OH) 3

The overall iron wire is lit in oxygen, forming a scale - iron oxide (II, III):

3Fe + 2O 2 → Fe 3 O 4

3Fe + 2O 2 → (Fe 2 III) O 4 (160 ° С)

2) at high temperatures (700-900 ° C) iron reacts with water vapor:

3FE + 4H 2 O - T ° → Fe 3 O 4 + 4H 2

3) Iron reacts with non-metals when heated:

2fe + 3Cl 2 → 2FeCl 3 (200 ° C)

Fe + S - T ° → FES (600 ° C)

Fe + 2S → Fe +2 (S 2 -1) (700 ° C)

4) In a row of stresses, it is up to the left of hydrogen, reacts with dilute NCl and H 2 SO 4 acids, while iron (II) salts are formed and hydrogen is distinguished:

Fe + 2HCl → FECL 2 + H 2 (reactions are carried out without air access, otherwise Fe +2 is gradually translated by oxygen in Fe +3)

Fe + H 2 SO 4 (RSC) → FESO 4 + H 2

In concentrated acid-oxidizers, iron is dissolved only when heated, it immediately goes into the Fe 3+ cation:

2fe + 6h 2 SO 4 (conc.) - T ° → Fe 2 (SO 4) 3 + 3SO 2 + 6H 2 O

Fe + 6hno 3 (conc.) - T ° → Fe (NO 3) 3 + 3NO 2 + 3H 2 O

(in the cold concentrated nitrogen and sulfuric acid passivate

The iron nail immersed in a bluish solution of copper sulfate is gradually covered with a red metal copper.

5) Iron outstanding metals with the right of it in solutions of their salts.

Fe + Cuso 4 → Feso 4 + Cu

Iron amphoterity is manifested only in concentrated alkalis when boiling:

Fe + 2NAON (50%) + 2H 2 O \u003d NA 2 ↓ + H 2

and the sediment of the tetrahydroxerrate (II) sodium is formed.

Technical iron - Iron alloys with carbon: cast iron contains 2.06-6.67% C, steel 0.02-2.06% C, often there are other natural impurities (s, p, si) and the artificially injected special additives (Mn, Ni, CR), which gives the iron alloys technically beneficial features - hardness, thermal and corrosion resistance, pupidity, etc. .

Dominal process of cast iron

The domain process of cast iron production is the following stages:

a) Preparation (firing) sulphide and carbonate ores - Translation into oxide ore:

FES 2 → Fe 2 O 3 (O 2, 800 ° C, -SO 2) FECO 3 → Fe 2 O 3 (O 2, 500-600 ° C, -CO 2)

b) Coke burning with hot blowing:

C (coke) + o 2 (air) → CO 2 (600-700 ° C) CO 2 + C (Coke) ⇌ 2 o (700-1000 ° С)

c) restoration of oxide ore carbon monoxide with consistently:

Fe 2 O 3 → (CO) (Fe II FE 2 III) O 4 → (CO) Feo. → (CO) FE.

d) carbonization of iron (up to 6.67% c) and cast iron melting:

Fe (T. ) →(C.(coke) 900-1200 ° С)Fe (g) (cast iron, t pl 1145 ° С)

FE 2 C and graphite cement is always present in the cast iron.

Steel production

The redistribution of cast iron in steel is carried out in special furnaces (converters, Martens, electrical), characterized by heating method; Process temperature 1700-2000 ° C. The blowing of air enriched with oxygen leads to burning from the cast iron of excess carbon, as well as sulfur, phosphorus and silicon in the form of oxides. At the same time, oxides are either captured in the form of exhaust gases (CO 2, SO 2), or bind to an easily separated slag - the mixture of Ca 3 (PO 4) 2 and CASIO 3. To obtain special steels into the furnace, alloying additives of other metals are introduced.

Obtaining Pure iron in industry - electrolysis of iron salts solution, for example:

FESL 2 → FE ↓ + CL 2 (90 ° C) (electrolysis)

(There are other special methods, including the restoration of iron oxides with hydrogen).

Clean iron is used in the production of special alloys, in the manufacture of cores of electromagnets and transformers, cast iron - in the production of casting and steel, steel - as structural and instrumental materials, including wear and heat and corrosion-resistant.

Iron oxide (II) F. eO . Amphoteric oxide with a large predominance of basic properties. Black, has an ionic structure Fe 2+ O 2-. When heated, it is first decomposed, then it is formed again. Not formed when combustion of iron in air. Does not react with water. Decomposes with acids, melted with alkalis. Slowly oxidized in wet air. Restored by hydrogen, coke. Participates in the domain process of cast iron. It is used as a component of ceramics and mineral paints. Equations of the most important reactions:

4Feo ⇌ (Fe II FE 2 III) + Fe (560-700 ° C, 900-1000 ° C)

FEO + 2NC1 (RSC) \u003d FES1 2 + H 2 O

FEO + 4NO 3 (conc.) \u003d Fe (NO 3) 3 + NO 2 + 2N 2 O

FEO + 4None \u003d 2N 2 O + N.a 4.F.e.O. 3 (Krasn..) trioFoferrat (II)(400-500 ° С)

FEO + H 2 \u003d H 2 O + FE (especially clean) (350 ° C)

FEO + C (Coke) \u003d Fe + Co (above 1000 ° C)

FEO + CO \u003d FE + CO 2 (900 ° C)

4Feo + 2H 2 O (moisture) + o 2 (air) → 4Feo (O) (T)

6Feo + O 2 \u003d 2 (Fe II FE 2 III) O 4 (300-500 ° C)

Obtaining in laboratories: Thermal decomposition of iron (II) compounds without air access:

Fe (OH) 2 \u003d FEO + H 2 O (150-200 ° C)

FENZE \u003d FEO + CO 2 (490-550 ° C)

Domeleza (III) - iron (III) oxide ( II. ) ( Fe II FE 2 III) O 4 . Double oxide. Black, has an ionic structure Fe 2+ (Fe 3+) 2 (O 2-) 4. Termically resistant to high temperatures. Does not react with water. Decomposes with acids. Restored by hydrogen, hot iron. Participates in the domain process of the production of cast iron. It is used as a component of mineral paints ( iron Surik), ceramics, color cement. Product of special oxidation of the surface of steel products ( blind, Blows). According to the composition corresponds to brown rust and dark abalin on the gland. The use of the FE 3 O 4 gross formula is not recommended. Equations of the most important reactions:

2 (Fe II FE 2 III) O 4 \u003d 6Feo + O 2 (above 1538 ° C)

(Fe 2 III) O 4 + 8ns1 (RSC) \u003d FES1 2 + 2FES1 3 + 4N 2 O

(Fe 2 III) O 4 + 10NNO 3 (conc.) \u003d 3Fe (NO 3) 3 + NO 2 + 5N 2 O

(Fe II FE 2 III) O 4 + O 2 (air) \u003d 6Fe 2 O 3 (450-600 ° С)

(Fe II FE 2 III) O 4 + 4N 2 \u003d 4N 2 O + 3FE (especially clean, 1000 ° C)

(Fe II FE 2 III) O 4 + CO \u003d ZFEO + CO 2 (500-800 ° C)

(Fe II FE 2 III) O4 + FE ⇌4Feo (900-1000 ° C, 560-700 ° C)

Getting: Iron combustion (see) in air.

magnetite.

Iron oxide (III) F. e 2 O 3 . Amphoteric oxide with the predominance of basic properties. Red-brown, has an ionic structure (Fe 3+) 2 (O 2-) 3. It is thermally stable to high temperatures. Not formed when combustion of iron in air. Does not react with water, a brown amorphous hydrate Fe 2 O 3 NN 2 O is dropping from the solution. Slowly reacts with acids and alkalis. Restores carbon monoxide, molten iron. Filts with oxides of other metals and forms double oxides - spinel (Technical products are called ferrites). It is used as raw materials when smelting cast iron in a domain process, a catalyst in the production of ammonia, a component of ceramics, color cements and mineral paints, with thermal welding of steel structures, as a carrier of sound and images on magnetic tapes, as a polishing agent for steel and glass.

Equations of the most important reactions:

6Fe 2 O 3 \u003d 4 (Fe 2 III) O 4 + O 2 (1200-1300 ° С)

Fe 2 O 3 + 6ns1 (RSS.) → 2FES1 3 + ZN 2 O (T) (600 ° C, R)

Fe 2 O 3 + 2NAON (conc.) → H 2 O + 2 N.butF.e.O. 2 (Krasn.)dioxoperrate (III)

Fe 2 O 3 + MO \u003d (M II FE 2 II I) O 4 (M \u003d Cu, Mn, Fe, Ni, Zn)

Fe 2 O 3 + zn 2 \u003d zn 2 o + 2Fe (especially clean, 1050-1100 ° С)

Fe 2 O 3 + Fe \u003d CFEO (900 ° C)

3Fe 2 O 3 + CO \u003d 2 (Fe II 2 III) O 4 + CO 2 (400-600 ° C)

Obtaining In the laboratory - thermal decomposition of iron salts (III) in air:

Fe 2 (SO 4) 3 \u003d Fe 2 O 3 + 3SO 3 (500-700 ° С)

4 (Fe (NO 3) 3 9 H 2 O) \u003d 2FE A O 3 + 12NO 2 + 3O 2 + 36N 2 O (600-700 ° C)

In nature - oxide iron ores hematite Fe 2 O 3 and limonite Fe 2 O 3 NN 2 O

Iron hydroxide (II) F. e (OH) 2. Amphoteric hydroxide with a predominance of basic properties. White (sometimes with a greenish tint), the connection Fe is predominantly covalent. Thermally unstable. Easily oxidized in air, especially in a wet state (darkest). Insoluble in water. Reacts with dilute acids concentrated alkalis. Typical reducing agent. Intermediate product when rusting iron. It is used in the manufacture of the active mass of ironoponecake batteries.

Equations of the most important reactions:

Fe (ON) 2 \u003d FEO + H 2 O (150-200 ° C, in atm.n 2)

Fe (OH) 2 + 2NC1 (RSC) \u003d FES1 2 + 2N 2 O

Fe () 2 + 2None (\u003e 50%) \u003d Na 2 ↓ (blue-green) (boiling)

4Fe (OH) 2 (suspension) + o 2 (air) → 4Feo (O) ↓ + 2N 2 O (t)

2F (OH) 2 (suspension) + H 2 O 2 (sample) \u003d 2Feo (O) ↓ + 2N 2 O

Fe (OH) 2 + KNO 3 (conc.) \u003d FEO (OH) ↓ + no + con (60 ° C)

Obtaining: precipitation from the solution with alkalis or ammonia hydrate in an inert atmosphere:

Fe 2+ + 2OH (RSC) \u003d F.e (OH) 2 ↓

Fe 2+ + 2 (NH 3 H 2 O) \u003d F.e (OH) 2 ↓+ 2NH 4.

Metagidroxide Iron F. eO. Amphoteric hydroxide with a predominance of basic properties. Light brown, Communication FE - O and FE - it is predominantly covalent. When heated decomposes without melting. Insoluble in water. The solution is precipitated from the solution in the form of a brown amorphous polyhydrate F 2 O 3 NN 2 O, which, when withstanding under the diluted alkaline solution, or when drying, goes into the FEO (OH). Reacts with acids, solid alkalis. Weak oxidizer and reducing agent. It sins with Fe (OH) 2. Intermediate product when rusting iron. It is used as the base of yellow mineral paints and enamels, the absorber of waste gases, a catalyst in organic synthesis.

The compound of the composition F (OH) 3 is not known (not received).

Equations of the most important reactions:

Fe 2 O 3. NN 2 O → ( 200-250 ° C, -H. 2 O.) FEO (OH) → ( 560-700 ° С in air, -h2o)→ Fe 2 o 3

FEO (OH) + ZNS1 (RSC) \u003d FES1 3 + 2N 2 O

Feo (OH) → FE. 2 O. 3 . nH. 2 O. -colloid (NAON (conc.))

FEO (OH) → N.and 3 [F.e (he) 6]white , NA 5 and K 4, respectively; In both cases, the blue product falls the same composition and structure, KFE III. In the laboratory, this precipitate is called prussian blue, or tournbull Xin:

Fe 2+ + K + + 3- \u003d KFE III ↓

Fe 3+ + K + + 4- \u003d KFE III ↓

Chemical names of the initial reagents and reaction products:

K 3 FE III - Hexacyanoferrat (III) Potassium

K 4 FE III - hexaciaranrat (II) potassium

KFE III - Hexacyanoferrat (II) Iron (W) Potassium

In addition, a good reagent on the FE 3+ ions is a thiocyanate-ion ion -, iron (III) connects to it, and bright red ("bloody") appears:

Fe 3+ + 6nss - \u003d 3-

This reagent (for example, in the form of KNSS salt), it can be detected even traces of iron (III) in tap water, if it passes through the iron pipes coated from the inside rust.