Classification of inorganic compounds conclusion. Relativity of substance classifications
The classification of inorganic substances is based on their degradability. Simple substances, consisting of atoms of only one chemical element(O 2 , H 2 , Mg) do not decompose. Complex substances consisting of atoms of two or more elements (CO 2 , H 2 SO 4 , NaOH, KCl) easily decompose.
Simple
The classification of classes of inorganic substances includes:
- metals - elements with thermal and electrical conductivity, high plasticity, malleability, metallic luster;
- nonmetals - more fragile than metals, elements that do not have electrical conductivity and exhibit oxidizing properties.
Rice. 1. Scheme for the classification of inorganic substances.
Metals are located in the lower left corner of the periodic table, non-metals in the upper right corner and include the noble gases.
Rice. 2. Arrangement of metals and non-metals in the periodic table.
Many simple chemical elements have allotropy - the property to form several simple substances. For example, when one more atom is attached to oxygen, a simple substance ozone (O 3) is formed, carbon, depending on the number of atoms, forms graphite, coal or diamond.
Complex
Compounds are classified into the following classes:
- oxides - consist of two elements, one of which is oxygen;
- acids - consist of hydrogen atoms and an acid residue;
- grounds - consist of a metal and one or more hydroxyl groups;
- salt - consist of a metal and an acid residue.
Separately, amphoteric hydroxides are isolated, which exhibit the properties of acids and bases. These are solids that are weak electrolytes. These include metal hydroxides with an oxidation state of +3 and +4. The exceptions are Be(OH) 2 , Zn(OH) 2 , Sn(OH) 2 , Pb(OH) 2 .
A more detailed classification of complex substances is presented in the table with examples.
View |
Nomenclature |
Chemical properties |
Example |
Oxides - E x O y |
Element oxide (oxidation state) |
There are basic oxides, which, when interacting with acids, form salts, and acid oxides, which form acids when interacting with bases. Separately, amphoteric oxides are isolated that interact with acids and bases (salt is formed) |
Na 2 O - sodium oxide, Fe 2 O 3 - iron oxide (III), N 2 O 5 - nitrogen oxide (V) |
Bases - Me (OH) x |
Metal hydroxide (oxidation state) |
In accordance with the solubility, alkalis and water-insoluble bases are isolated. Alkalis interact with non-metals and acidic oxides. Insoluble bases react with acids and can decompose at high temperatures |
Fe (OH) 2 - iron (II) hydroxide, Cu (OH) 2 - copper (II) hydroxide, NaOH - sodium hydroxide |
Acids - H n Ac |
It is read depending on the acid residue |
They interact with metals to the left of hydrogen in the activity series, with oxides, salts. Capable of decomposing at high temperatures |
H 2 SO 4 - sulfuric acid, HCl - hydrochloric acid, HNO 3 - nitric acid |
Salts - Me x (Ac) y |
Acid residue of the metal (oxidation state) |
React with acids, alkalis, metals and salts |
Na 2 SO 4 - sodium sulfate, CaCO 3 - calcium carbonate, KCl - potassium chloride |
Rice. 3. List of names of acids.
Genetic links between classes are based on the mutual transformation of substances. At chemical reactions atoms pass from one substance to another, forming genetic series (series of transformations). The metal, when oxygen is added, forms an oxide, which, when interacting with water, turns into a base. An acidic oxide is formed from a non-metal, which, interacting with water, forms an acid. Any genetic series ends with salt.
What have we learned?
Inorganic substances include simple and complex compounds. Simple substances are made up of atoms of the same element. These include metals and non-metals. Complex compounds include substances consisting of several elements. These include oxides, acids, bases, salts and amphoteric hydroxides. All substances are genetically related. From a simple substance, a more complex substance can be obtained. Salts are considered the most complex substances.
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Simple substances. Molecules are made up of atoms of the same kind (atoms of the same element). In chemical reactions, they cannot decompose to form other substances.
Complex substances (or chemical compounds). Molecules are made up of atoms different kind(atoms of various chemical elements). In chemical reactions, they decompose to form several other substances.
There is no sharp boundary between metals and non-metals, because there are simple substances that exhibit dual properties.
Allotropy
Allotropy- the ability of some chemical elements to form several simple substances that differ in structure and properties.
C - diamond, graphite, carbine.
O - oxygen, ozone.
S - rhombic, monoclinic, plastic.
P - white, red, black.
The phenomenon of allotropy is caused by two reasons:
1) a different number of atoms in a molecule, for example, oxygen O 2 and ozone O 3
2) the formation of various crystalline forms, such as diamond and graphite.
GROUNDS
Foundations- complex substances in which metal atoms are connected to one or more hydroxyl groups (from the point of view of the theory electrolytic dissociation, bases are complex substances, during the dissociation of which metal cations (or NH 4 +) and hydroxide - anions OH - are formed in an aqueous solution.
Classification. Soluble in water (alkali) and insoluble. Amphoteric bases also exhibit the properties of weak acids.
Receipt
1. Reactions of active metals (alkali and alkaline earth metals) with water:
2Na + 2H 2 O ® 2NaOH + H 2 -
Ca + 2H 2 O ® Ca (OH) 2 + H 2 -
2. Interaction of active metal oxides with water:
BaO + H 2 O ® Ba (OH) 2
3. Electrolysis of aqueous solutions of salts
2NaCl + 2H 2 O ® 2NaOH + H 2 - + Cl 2 -
Chemical properties
alkalis | Insoluble bases |
1. Action on indicators. | |
litmus - blue methyl orange - yellow phenolphthalein - raspberry |
-- |
2. Interaction with acid oxides. | |
2KOH + CO 2 ® K 2 CO 3 + H 2 O KOH + CO 2 ® KHCO 3 |
-- |
3. Interaction with acids (neutralization reaction) | |
NaOH + HNO 3 ® NaNO 3 + H 2 O | Cu(OH) 2 + 2HCl ® CuCl 2 + 2H 2 O |
4. Exchange reaction with salts | |
Ba(OH) 2 + K 2 SO 4 ® 2KOH + BaSO 4 ¯ 3KOH+Fe(NO 3) 3 ® Fe(OH) 3 ¯ + 3KNO 3 |
-- |
5. Thermal decomposition. | |
-- | Cu(OH) 2 - t ° ® CuO + H 2 O |
OXIDES
Classification
oxides- These are complex substances consisting of two elements, one of which is oxygen.
OXIDES | |
Non-salt-forming | CO, N2O, NO |
Salt-forming | Main - these are metal oxides, in which the latter exhibit a small oxidation state of +1, +2 Na 2 O; MgO CuO |
|
Amphoteric (usually for metals with an oxidation state of +3, +4). As hydrates, they correspond to amphoteric hydroxides ZnO; Al 2 O 3 ; Cr2O3; SnO 2 |
|
Acidic - these are oxides of non-metals and metals with an oxidation state from +5 to +7 SO2; SO3; P 2 O 5 ; Mn 2 O 7 ; CrO3 |
|
Basic oxides match the bases acidic- acids, amphoteric- and those and others |
Receipt
1. Interaction of simple and complex substances with oxygen:
2Mg + O 2 ® 2MgO
4P + 5O 2 ® 2P 2 O 5
S + O 2 ® SO 2
2CO + O 2 ® 2CO 2
2CuS + 3O 2 ® 2CuO + 2SO 2
CH 4 + 2O 2 ® CO 2 + 2H 2 O
4NH 3 + 5O 2 - cat. ® 4NO + 6H 2 O
2. Decomposition of some oxygen-containing substances (bases, acids, salts) when heated:
Cu(OH) 2 - t ° ® CuO + H 2 O
(CuOH) 2 CO 3 - t ° ® 2CuO + CO 2 + H 2 O
2Pb (NO 3) 2 - t ° ® 2PbO + 4NO 2 + O 2
2HMnO 4 - t °; H 2 SO 4 (conc.) ® Mn 2 O 7 + H 2 O
Chemical properties
Basic oxides | Acid oxides |
1. Interaction with water | |
The base is formed: Na 2 O + H 2 O ® 2NaOH CaO + H 2 O ® Ca (OH) 2 |
Acid is formed: SO 3 + H 2 O ® H 2 SO 4 P 2 O 5 + 3H 2 O ® 2H 3 PO 4 |
2. Interaction with acid or base: | |
When reacting with acid salt and water are formed MgO + H 2 SO 4 - t ° ® MgSO 4 + H 2 O CuO + 2HCl - t ° ® CuCl 2 + H 2 O |
When reacting with a base salt and water are formed CO 2 + Ba(OH) 2 ® BaCO 3 + H 2 O SO 2 + 2NaOH ® Na 2 SO 3 + H 2 O |
Amphoteric oxides interact | |
with acids as basic: ZnO + H 2 SO 4 ® ZnSO 4 + H 2 O |
with bases as acidic: ZnO + 2NaOH ® Na 2 ZnO 2 + H 2 O (ZnO + 2NaOH + H 2 O ® Na 2 ) |
3. The interaction of basic and acidic oxides with each other leads to salts. | |
Na 2 O + CO 2 ® Na 2 CO 3 | |
4. Recovery to simple substances: | |
3CuO + 2NH 3 ® 3Cu + N 2 + 3H 2 O P 2 O 5 + 5C ® 2P + 5CO |
Simple substances. Molecules are made up of atoms of the same kind (atoms of the same element). In chemical reactions, they cannot decompose to form other substances.
Complex substances (or chemical compounds). Molecules are made up of different types of atoms (atoms of different chemical elements). In chemical reactions, they decompose to form several other substances.
There is no sharp boundary between metals and non-metals, because there are simple substances that exhibit dual properties.
Allotropy
Allotropy- the ability of some chemical elements to form several simple substances that differ in structure and properties.
C - diamond, graphite, carbine.
O - oxygen, ozone.
S - rhombic, monoclinic, plastic.
P - white, red, black.
The phenomenon of allotropy is caused by two reasons:
1) a different number of atoms in a molecule, for example, oxygen O 2 and ozone O 3
2) the formation of various crystalline forms, such as diamond and graphite.
GROUNDS
Foundations- complex substances in which metal atoms are connected to one or more hydroxyl groups (from the point of view of the theory of electrolytic dissociation, bases are complex substances, during the dissociation of which metal cations (or NH 4 +) and hydroxide - anions OH - are formed in an aqueous solution) .
Classification. Soluble in water (alkali) and insoluble. Amphoteric bases also exhibit the properties of weak acids.
Receipt
1. Reactions of active metals (alkali and alkaline earth metals) with water:
2Na + 2H 2 O ® 2NaOH + H 2 -
Ca + 2H 2 O ® Ca (OH) 2 + H 2 -
2. Interaction of active metal oxides with water:
BaO + H 2 O ® Ba (OH) 2
3. Electrolysis of aqueous solutions of salts
2NaCl + 2H 2 O ® 2NaOH + H 2 - + Cl 2 -
Chemical properties
alkalis | Insoluble bases |
1. Action on indicators. | |
litmus - blue methyl orange - yellow phenolphthalein - raspberry |
-- |
2. Interaction with acid oxides. | |
2KOH + CO 2 ® K 2 CO 3 + H 2 O KOH + CO 2 ® KHCO 3 |
-- |
3. Interaction with acids (neutralization reaction) | |
NaOH + HNO 3 ® NaNO 3 + H 2 O | Cu(OH) 2 + 2HCl ® CuCl 2 + 2H 2 O |
4. Exchange reaction with salts | |
Ba(OH) 2 + K 2 SO 4 ® 2KOH + BaSO 4 ¯ 3KOH+Fe(NO 3) 3 ® Fe(OH) 3 ¯ + 3KNO 3 |
-- |
5. Thermal decomposition. | |
-- | Cu(OH) 2 - t ° ® CuO + H 2 O |
OXIDES
Classification
oxides- These are complex substances consisting of two elements, one of which is oxygen.
OXIDES | |
Non-salt-forming | CO, N2O, NO |
Salt-forming | Main - these are metal oxides, in which the latter exhibit a small oxidation state of +1, +2 Na 2 O; MgO CuO |
|
Amphoteric (usually for metals with an oxidation state of +3, +4). As hydrates, they correspond to amphoteric hydroxides ZnO; Al 2 O 3 ; Cr2O3; SnO 2 |
|
Acidic - these are oxides of non-metals and metals with an oxidation state from +5 to +7 SO2; SO3; P 2 O 5 ; Mn 2 O 7 ; CrO3 |
|
Basic oxides match the bases acidic- acids, amphoteric- and those and others |
Receipt
1. Interaction of simple and complex substances with oxygen:
2Mg + O 2 ® 2MgO
4P + 5O 2 ® 2P 2 O 5
S + O 2 ® SO 2
2CO + O 2 ® 2CO 2
2CuS + 3O 2 ® 2CuO + 2SO 2
CH 4 + 2O 2 ® CO 2 + 2H 2 O
4NH 3 + 5O 2 - cat. ® 4NO + 6H 2 O
2. Decomposition of some oxygen-containing substances (bases, acids, salts) when heated:
Cu(OH) 2 - t ° ® CuO + H 2 O
(CuOH) 2 CO 3 - t ° ® 2CuO + CO 2 + H 2 O
2Pb (NO 3) 2 - t ° ® 2PbO + 4NO 2 + O 2
2HMnO 4 - t °; H 2 SO 4 (conc.) ® Mn 2 O 7 + H 2 O
Chemical properties
Basic oxides | Acid oxides |
1. Interaction with water | |
The base is formed: Na 2 O + H 2 O ® 2NaOH CaO + H 2 O ® Ca (OH) 2 |
Acid is formed: SO 3 + H 2 O ® H 2 SO 4 P 2 O 5 + 3H 2 O ® 2H 3 PO 4 |
2. Interaction with acid or base: | |
When reacting with acid salt and water are formed MgO + H 2 SO 4 - t ° ® MgSO 4 + H 2 O CuO + 2HCl - t ° ® CuCl 2 + H 2 O |
When reacting with a base salt and water are formed CO 2 + Ba(OH) 2 ® BaCO 3 + H 2 O SO 2 + 2NaOH ® Na 2 SO 3 + H 2 O |
Amphoteric oxides interact | |
with acids as basic: ZnO + H 2 SO 4 ® ZnSO 4 + H 2 O |
with bases as acidic: ZnO + 2NaOH ® Na 2 ZnO 2 + H 2 O (ZnO + 2NaOH + H 2 O ® Na 2 ) |
3. The interaction of basic and acidic oxides with each other leads to salts. | |
Na 2 O + CO 2 ® Na 2 CO 3 | |
4. Recovery to simple substances: | |
3CuO + 2NH 3 ® 3Cu + N 2 + 3H 2 O P 2 O 5 + 5C ® 2P + 5CO |
For elements included in the periodic system (PS) of elements D.I. Mendeleev, it is allowed to use the following group names, reflecting, as a rule, general properties elements and simple substances. For elements main subgroups in the short-term version of PS
or 1-2 and 13-18 groups in the long-term (modern) version of PS
- alkaline metals (1st or IA group): (H), Li, Na, K, Rb, Cs, Fr;
- alkaline earth(except Mg) metals (2nd or IIAg group): Be, Mg, Ca, Sr, Ba, Ra;
- elements boron subgroups(group 13 or IIIA), metals (apart from boron), do not have a special name: B, Al, Ga, In, Ti;
- elements subgroups of carbon(14th or IVA group) or crystallogens: C, Si, Ge, Sn, Pb;
- elements nitrogen subgroups(15th or VA group), obsolete name pnicogensand its derivativepnictides: N, P, As, Sb, Bi;
- elements oxygen subgroups(16 or VIA group) orchalcogens ,
- halogens(17th or VIIA group),
- noble or inertgases (18th or VIIIA group)
For elements side subgroups:
- lanthanides(La-Lu)
- actinides(Ac – Lr) (names of lanthanides and actinides are not recommended);
- rare earth metals(3rd or IIIB group, except for actinides);
- iron family(Fe, Co, Ni);
- platinum family or platinum metals(Ru, Rh, Pd, Os, Ir, Pt);
- precious metals(Au, Ag + platinum: Ru, Rh, Pd, Os, Ir, Pt)
- transition elements(d and f-elements, that is, all elements of secondary subgroups).
Simple substances are called, as a rule, in the same way as the corresponding elements. Their own names have only allotropic modifications carbon (diamond, graphite, carbine, fullerenes) and the second modification of oxygen (ozone). With names allotropic modifications other elements usually indicate its brief physical characteristics (white, red, black phosphorus, crystalline and plastic sulfur, gray and white tin, etc.).
The elements oxygen, nitrogen, carbon and sulfur in compounds with metals or with less electronegative non-metals can form anions not only in their characteristic negative oxidation states ($O^(2-), S^(2-), N^(3- ), C^(4-)$, but also ions, in which the oxidation states of an element depend on the number of atoms in the "bridge" structures. organic compounds is determined by special methods (see the topic "Determination of the degree of oxidation of carbon"). For example, the element oxygen can form peroxide and supraperoxide ions, in which the oxygen atoms form "oxygen bridges" -O-O- or -O-O-O-. Such anions have their own names: $(O_2)^(2-)$ - peroxide; $(O_2)^-$ - superoxide; $(O_3)^-$ - ozonide; $(N_3)^-$ - azide; $(С_2)^(2-)$ - acetylenide; $(S_2)^(2-)$ - disulfide; $(Sn)^(2-)$ - polysulfide.
The names of some stable anions, consisting of atoms of more than one element, traditionally also have -id endings: $(OH)^-$ - hydroxide; $(CN)^-$ - cyanide; $(CN_2)^(2-)$ - cyanamide; $(NH_2)^-$ - amide; $(NH)^(2-)$ - imide; $(SCN)^-$ - thiocyanate.
CLASSIFICATION OF INORGANIC SUBSTANCES
General principles for the classification of inorganic substances are presented in the diagram. Based on this classification, all inorganic substances can be divided into simple and complex.
Definition
Simple substances made up of atoms identical elements and are subdivided into metals, non-metals and inert gases.
Complex Substances They are made up of atoms of different elements that are chemically bonded to each other.
In turn, based on the commonality of properties, complex inorganic substances can be divided into four main classes: binary compounds, oxides, hydroxides, salts.
The classification and nomenclature of binary compounds is discussed in detail in the topic "Binary compounds".
CLASSIFICATION AND FEATURES OF THE PROPERTIES OF OXIDES
Definition
Oxides called binary chemical compounds consisting of elements of metals or non-metals and oxygen. Or, in other words, oxides are complex substances consisting of two elements, one of which is oxygen.
The classification of oxides is based on the chemical properties of compounds due to chemical structure(that is, the type of bonds formed and the type of crystal lattice, the structure and electronic characteristics of the elements).
By physical properties oxides vary state of aggregation, melting and boiling points, color, smell, solubility in water.
According to the state of aggregation, oxides are:
- solid (all metal oxides, silicon oxide, phosphorus oxide),
- liquid (water $H_2O$),
- gaseous (practically all other non-metal oxides).
By chemical properties, oxides are divided into non-salt-forming and salt-forming.
Definition
Salt-forming are oxides capable of forming hydroxides when combined with water.
The latter, in turn, can exhibit the properties of acids, bases, or have amphoteric properties. Therefore, salt-forming oxides are usually divided into basic, acidic and amphoteric.
CLASSIFICATION of acids and bases
From the initial chemistry course, you are familiar with the following definition of acids and bases:
Definition
acids- these are complex substances consisting of hydrogen atoms that can be replaced by metal atoms, and acid residues. The general formula of acids is: $H_x(Ac)^(-n)$, where Ac is the acid residue (acid is an English acid), x is the number of hydrogen atoms, n is the oxidation state of the acid residue. In acids x=n.
Definition
Foundations(hydroxides) are complex substances consisting of metal atoms and one or more hydroxo groups (-OH). The general formula of bases is: $M^(+n)(OH)_x$, where n is the oxidation state of the metal, x is the number of hydroxyl groups. n=x.
It should be noted that both bases and acids belong to the class of hydroxides, since they contain hydroxo groups (-OH). Therefore, acids are also called acidic hydroxides and bases are also called basic hydroxides.
Acid-base interactions are extremely common in nature and are widely used in scientific and industrial practice. The theory of acids and bases is a set of fundamental physical and chemical concepts that describe the nature and properties of acids and bases. In addition to the usual definition of the 8th grade, there are other theories:
Theory | Content | Examples |
---|---|---|
Arrhenius theory of electrolytic dissociation |
acids- these are substances that form ions in an aqueous solution - hydrated hydrogen cations $H^+$ (hydronium ions $H_3O$) and anions of an acid residue, or in other words, these are electrolytes that dissociate into hydrogen cations and anions of an acid residue. Foundations- complex substances-electrolytes, dissociating with the formation of a hydroxide ion and a metal cation. |
$NaOH \Leftrightarrow Na^+ + OH^-$ base $HNO_3 \Leftrightarrow H^+ + NO_3^-$ acid |
Bronsted's protolithic theory |
acids- these are complex substances that, as a result of a heterolytic gap, give off a particle with a positive charge - a hydrogen proton (Brensted's acid) Base is a chemical compound capable of forming covalent bond with proton (Brønsted base) |
$HCl + NH_3 = NH_4^+ + Cl^-$ to-that basic to-that basic |
Lewis theory |
Acid- a molecule or ion that has vacant electron orbitals, which is an electron pair acceptor (Lewis acid) Base is a chemical compound capable of forming a covalent bond with the vacant orbital of another chemical compound |
This topic is covered in more detail in the " Modern concepts on the structure and properties of acids and bases.
Acid classification
is carried out according to the following formal criteria:
1. by basicity that is, the number of hydrogen atoms: one- ($HCl$), two- ($H_2S$) and tribasic ($H_3PO_4$);
2. by the presence of oxygen atoms: oxygen-containing ($H_2CO_3$) and anoxic (HCL);
3. by strength that is, the degree of dissociation: strong ($HCl, HNO_3, H_2SO_4, HClO_4$, etc.), weak ($H_2S, H_2CO_3, CH_3COOH$, etc.)
4. in terms of sustainability: persistent ($H_2SO_4$); unstable ($H_2CO_3$).
5. by belonging to the classes of chemical compounds: inorganic (HBr); organic ($HCOOH,CH_3COOH$);
6.by volatility: volatile ($HNO_3,H_2S, HCl$); non-volatile ($H_2SO_4$);
7. by solubility in water: soluble ($H_2SO_4$); insoluble ($H_2SiO_3$);
Base classification
is carried out according to the following formal criteria::
1. by acidity(number of hydroxyl groups): one-acid (NaOH), two-acid ($Ca(OH)_2$), three-acid ($Al(OH)_3$)
2. by solubility: alkalis or soluble bases ($KOH, NaOH$), insoluble ($Mg(OH)_2, Cu(OH)_2$)
3. by strength(degrees of dissociation): strong (NaOH), weak ($Cu(OH)_2$)
** Do not confuse the strength of the base and its solubility. For example, calcium hydroxide is a strong base, although its solubility in water is not great. In this case, a strong base (alkali) is considered to be that part of calcium hydroxide that is dissolved in water.
AMPHOTERIC HYDROXIDES
Definition
Amphoteric hydroxides are complex substances that exhibit both the properties of acids and the properties of bases.
The formula of amphoteric hydroxides can be written both as an acid and as a base, for example: aluminum hydroxide can be written in the form of a base as $Al(OH)_3$. If we count the total number of hydrogen and oxygen atoms, then we can write: $H_3ALO_3$ or the simplest formula- $HAlo_2$.
Amphoteric oxides and hydroxides are formed by amphoteric elements. Remember! Amphoteric properties are exhibited by metalloid elements: Al, Zn, B, Be, Fe(III), Cr(III) and some other transition elements that have different oxidation states and are located on the amphoteric diagonal in PS (see the topic "Periodic system as a conditional record of the periodic law"). The A‑group metals that form the amphoteric diagonal in the Be‑Al‑Ge‑Sb‑Po Periodic Table, as well as the metals adjacent to them (Ga, In, Tl, Sn, Pb, Bi) do not exhibit typically metallic properties.
The manifestation of duality (amphoteric) properties, both metallic (basic) and non-metallic, is due to the nature of the chemical bond.
CLASSIFICATION AND FEATURES OF SALT PROPERTIES
The definition of salts, as well as the definition of acids and bases, has several options. AT school course The 8th grade definition of salts is as follows:
Definition
Salts - these are complex substances consisting of metal cations (ammonium ion) and anions of acid residues. The general formula of salts is: $M^(+n)_xAc^(m-)_y$, where n, m are the oxidation states of the metal and acid residue, x, y are the number of atoms of the metal and acid residue, respectively. m=x and n=y
This definition refers to medium salts that are formed as a result of a neutralization reaction between an acid and a base, that is, they can be obtained by reacting acids and bases with the release of water. Therefore, a more accurate definition of average salts:
Definition
Medium salts- these are products of the complete replacement of hydrogen atoms in an acid molecule by metal atoms, or the complete replacement of hydroxo groups in a base molecule by acidic residues.
From the point of view of the theory of electrolytic dissociation (TED):
salt- these are complex substances that dissociate in aqueous solutions into metal cations and anions of acid residues.
The International Union of Pure and Applied Chemistry (IUPAC) defines salts as chemical compounds consisting of cations and anions.
Thus, the classification of salts can be carried out:
1.by solubility: soluble, slightly soluble and insoluble (you can determine which group the salt belongs to according to the solubility table)
2. according to the degree of substitution of hydrogen ions and hydroxyl groups: medium, sour, basic, double, mixed. The topic is discussed in more detail in the section "Classification and nomenclature of salts".
The table provides examples and definitions of acidic and basic salts.
medium | sour | main | double | |
---|---|---|---|---|
The product of the complete replacement of acid hydrogen by a metal | Product of incomplete replacement of acid hydrogen by metal (known only for polybasic acids) | Product of incomplete replacement of the hydroxyl groups of a base with an acidic residue (known only for polyacid bases) | Product of complete replacement of hydrogen atoms of a dibasic or polybasic acid by two different metals | |
Na$_2$SO$_4$ sodium sulfate CuCl$_2$ copper(II) chloride $Ca_3(PO_4)_2$ calcium orthophosphate |
sodium hydrogen sulfate CaHPO$_4$ Calcium hydrogen orthophosphate Ca(H$_2$PO$_4$)$_2$ calcium dihydroorthophosphate |
copper(II) hydroxochloride Ca$_5$(PO$_4$)$_3$(OH) calcium hydroxorthophosphate |
$NaKCO_3$ potassium sodium carbonate aluminum potassium sulfate |
A separate large class is complex salts, which are related to complex compounds.
Definition
Complex compounds or coordination compounds- particles (neutral molecules or ions) that are formed as a result of attachment to a given ion (or atom), called complexing agent, neutral molecules or other ions called ligands.
inner sphere complex compound - the central atom with ligands associated with it, that is, in fact, a complex particle.
outer sphere complex compound - other particles associated with a complex particle by ionic or intermolecular bonds, including hydrogen bonds.
For example, consider the structure of the complex salt $K_3$ - potassium hexacyanoferrate (III).
The inner sphere is formed by an iron (III) ion, therefore it is a complexing agent having an oxidation state of +3. Six $CN^-$ ions are coordinated around this ion. These are ligands, the coordination number is six. The total charge of the inner sphere is: (+3)+ (-1)x6=(-3).
The outer sphere is formed by potassium cations $K^+$. In accordance with the charge of the inner sphere, equal to (-3), there should be 3 potassium ions in the outer sphere.
Complex salts having an outer sphere in an aqueous solution completely dissociate into a complex low-dissociating cation or anion.
Complex compounds without outer sphere insoluble in water (for example, metal carbonyls).
The classification of inorganic substances and their nomenclature are based on the simplest and most constant characteristic over time -
chemical composition , which shows the atoms of the elements that form a given substance, in their numerical ratio. If a substance is made up of atoms of one chemical element, i.e. is a form of existence of this element in a free form, then it is called a simple substance; if the substance is made up of atoms of two or more elements, then it is called complex substance. All simple substances (except monatomic) and all complex substances are called chemical compounds , since in them the atoms of one or different elements are interconnected by chemical bonds.The nomenclature of inorganic substances consists of formulas and names. Chemical formula - representation of the composition of a substance using symbols of chemical elements, numerical indices and some other signs. chemical name - depiction of the composition of a substance using a word or group of words. The construction of chemical formulas and names is determined by the system nomenclature rules .
Symbols and names of chemical elements are given in the Periodic system of elements of D.I. Mendeleev. Elements are conditionally divided into metals
and nonmetals . Non-metals include all elements VIII A-groups (noble gases) and VII A-groups (halogens), elements VI A-groups (except for polonium), elements nitrogen, phosphorus, arsenic ( V A-group); carbon, silicon ( IVA-group); boron (III A-group), as well as hydrogen. The remaining elements are classified as metals.When compiling the names of substances, Russian names of elements are usually used, for example, dioxygen, xenon difluoride, potassium selenate. By tradition, for some elements, the roots of their Latin names are introduced into derivative terms:
Ag - argent |
N - nitr |
As - ars, arsene |
Ni - nikkol |
Au - aur |
O - ox, oxygen |
C - carb, carbon |
Pb - plumb |
Cu - cupre |
S - sulf |
Fe - ferr |
Sb - stib |
H - hydr, hydrogen |
Si- strength, silic, silic |
Hg - mercur |
Sn - stann |
Mn - manganese |
For example
: carbonate, manganate, oxide, sulfide, silicate.Titles simple substances consist of one word - the name of a chemical element with a numerical prefix, for example:
The following numerical prefixes
:
1 - mono |
7 - hepta |
2 - di |
|
3 - three |
9 - nona |
4 - tetra |
|
5 - penta |
11 - undeca |
6 - hexa |
12 - dodeca |
An indefinite number is indicated by a numerical prefix
n - poly.For some simple substances also use special names such as
3 - ozone, R 4 - white phosphorus.Chemical formulas complex substances are made up of the designation electropositive(conditional and real cations) and electronegative(conditional and real anions) components, for example,
CuSO 4 (here Cu 2+ - real cation, SO 4 2- - real anion) and PCl 3 (here P + III - conditional cation, Cl-I- conditional anion).Titles complex substances make up the chemical formulas from right to left. They consist of two words - the names of the electronegative components (in the nominative case) and the electropositive components (in genitive case), for example:
CuSO 4 - copper(II) sulfate The number of electropositive and electronegative components in the names is indicated by the numerical prefixes given above (universal method), or by the oxidation states (if they can be determined by the formula) using Roman numerals in parentheses (the plus sign is omitted). In some cases, the ion charge is given (for complex cations and anions), using Arabic numerals with the corresponding sign. The following special names are used for common multielement cations and anions:
PCl 3 - phosphorus trichloride
LaCl 3 - lanthanum(III) chloride
SO - carbon monoxide
H 2 F + - fluoronium |
C 2 2- - acetylenide |
H 3 O + - oxonium |
CN - - cyanide |
H 3 S + - sulfonium |
CNO - - fulminate |
NH 4 + - ammonium |
HF 2 - - hydrodifluoride |
N 2 H 5 + - hydrazinium (1+) |
HO 2 - - hydroperoxide |
N 2 H 6 + - hydrazinium (2+) |
HS - - hydrosulfide |
NH 3 OH + - hydroxylaminium |
N 3 - - azide |
NO + - nitrosyl |
NCS - - thiocyanate |
NO 2 + - nitroyl |
O 2 2 - - peroxide |
O 2 + - dioxygenyl |
O 2 - - superoxide |
PH 4 + - phosphonium |
O 3 - - ozonide |
VO 2 + - vanadyl |
OCN - - cyanate |
UO 2 + - uranyl |
OH - - hydroxide |
For a small number of well-known substances also use special titles:
AsH 3 - arsine |
HN 3 - hydrogen azidide |
B 2 H 6 - borane |
H 2 S - hydrogen sulfide |
B 4 H 10 - tetraborane (10) |
NH 3 - ammonia |
HCN - hydrogen cyanide |
N 2 H 4 - hydrazine |
HCl - hydrogen chloride |
NH 2 OH - hydroxylamine |
HF - hydrogen fluoride |
PH 3 - phosphine |
HI - hydrogen iodide |
SiH 4 - silane |
Hydroxides - a type of complex substances, which include atoms of a certain element E (except for fluorine and oxygen) and the hydroxo group OH; general formula of hydroxides E (OH)
n, where n= 1÷6. Hydroxide form E(OH)ncalled ortho -form; at n> 2 hydroxide can also be found in meta -form, including, in addition to E atoms and OH groups, O oxygen atoms, for example, E (OH) 3 and EO(OH), E(OH) 4 and E(OH) 6 and EO 2 (OH) 2 .Hydroxides are divided into two chemically opposite groups: acidic and basic hydroxides.
Acid hydroxides contain hydrogen atoms, which can be replaced by metal atoms, subject to the rule of stoichiometric valence. Most acid hydroxides are found in meta-form, and hydrogen atoms in the formulas of acid hydroxides are put in the first place, for example
H 2 SO 4, HNO 3 and H 2 CO 3, not SO 2 (OH) 2, NO 2 (OH) and CO (OH) 2 . The general formula of acid hydroxides is H X EO at, where the electronegative component EO at x- called an acid residue. If not all hydrogen atoms are replaced by a metal, then they remain in the composition of the acid residue.The names of common acid hydroxides consist of two words: the proper name with the ending “aya” and the group word “acid”. Here are the formulas and proper names of common acid hydroxides and their acid residues (a dash means that the hydroxide is not known in free form or in an acidic aqueous solution):
acid hydroxide |
acid residue |
HASO 2 - metaarsenic |
AsO 2 - - metaarsenite |
H 3 AsO 3 - orthoarsenic |
AsO 3 3- - orthoarsenite |
H 3 AsO 4 - arsenic |
AsO 4 3- - arsenate |
4 O 7 2- - tetraborate | |
iO 3 - - bismuthate | |
HBrO - bromine |
BrO - - hypobromite |
HBrO 3 - bromine |
BrO 3 - - bromate |
H 2 CO 3 - coal |
CO 3 2- - carbonate |
HClO - hypochlorous |
ClO- - hypochlorite |
HClO 2 - chloride |
ClO 2 - - chlorite |
HClO 3 - chlorine |
ClO 3 - - chlorate |
HClO 4 - chlorine |
ClO 4 - - perchlorate |
H 2 CrO 4 - chrome |
CrO 4 2- - chromate |
CrO4- - hydrochromate | |
H 2 Cr 2 O 7 - dichromic |
Cr 2 O 7 2- - dichromate |
FeO 4 2- - ferrate |
|
HIO 3 - iodine |
IO3- - iodate |
HIO 4 - metaiodine |
IO 4 - - metaperiodate |
H 5 IO 6 - orthoiodic |
IO 6 5- - orthoperiodate |
HMnO 4 - manganese |
MnO4- - permanganate |
MnO 4 2- - manganate |
|
Mo O 4 2- - molybdate |
|
HNO 2 - nitrogenous |
NO 2 - - nitrite |
HNO 3 - nitrogen |
NO 3 - - nitrate |
HPO 3 - metaphosphoric |
PO 3 - - metaphosphate |
H 3 PO 4 - orthophosphoric |
PO 4 3- - orthophosphate |
PO 4 2- - hydrogen orthophosphate | |
2 PO 4 - - dihydrootophosphate | |
H 4 P 2 O 7 - diphosphoric |
P 2 O 7 4- - diphosphate |
ReO 4 - - perrhenate |
|
SO 3 2- - sulfite |
|
HSO 3 - - hydrosulfite |
|
H 2 SO 4 - sulfuric |
SO 4 2- - sulfate |
SO 4 - - hydrosulphate | |
H 2 S 2 O 7 - dispersed |
S 2 O 7 2- - disulfate |
H 2 S 2 O 6 (O 2) - peroxodisulphuric |
S 2 O 6 (O 2) 2- - peroxodisulfate |
H 2 SO 3 S - thiosulfuric |
SO 3 S 2- - thiosulfate |
H 2 SeO 3 - selenium |
SeO 3 2- - selenite |
H 2 SeO 4 - selenium |
SeO 4 2- - selenate |
H 2 SiO 3 - metasilicon |
SiO 3 2- - metasilicate |
H 4 SiO 4 - orthosilicon |
SiO 4 4- - orthosilicate |
H 2 TeO 3 - telluric |
TeO 3 2- - tellurite |
H 2 TeO 4 - metatellurium |
TeO 4 2- - metatellurate |
H 6 TeO 6 - orthotelluric |
TeO 6 6- - orthotellurate |
VO3- - metavanadate |
|
VO 4 3- - orthovanadate |
|
WO 4 3- - tungstate |
Less common acid hydroxides are named according to the nomenclature rules for complex compounds, for example:
The names of acid residues are used in the construction of the names of salts.
Basic hydroxides contain hydroxide ions, which can be replaced by acidic residues, subject to the rule of stoichiometric valency. All basic hydroxides are found in ortho-form; their general formula is M(OH)
n, where n= 1.2 (rarely 3.4) and M n +- metal cation. Examples of formulas and names of basic hydroxides:The most important chemical property of basic and acid hydroxides is their interaction with each other with the formation of salts ( salt formation reaction), for example:
Ca (OH) 2 + H 2 SO 4 \u003d CaSO 4 + 2H 2 O
Ca (OH) 2 + 2H 2 SO 4 \u003d Ca (HSO 4) 2 + 2H 2 O
2Ca(OH) 2 + H 2 SO 4 = Ca 2 SO 4 (OH) 2 + 2H 2 O
salt - type of complex substances, which include cations M
n+ and acid residues*.Salts with the general formula M X(EO at
)n called average salts, and salts with unsubstituted hydrogen atoms - sour salts. Sometimes salts also contain hydroxide and/or oxide ions; such salts are called main salts. Here are examples and names of salts:
- calcium orthophosphate |
|
- calcium dihydroorthophosphate |
|
- calcium hydrogen phosphate |
|
Copper(II) carbonate |
|
Cu 2 CO 3 (OH) 2 |
- dicopper dihydroxide carbonate |
Lanthanum(III) nitrate |
|
- titanium oxide dinitrate |
Acid and basic salts can be converted to medium salts by reaction with the corresponding basic and acidic hydroxide, for example:
Ca (HSO 4) 2 + Ca (OH) \u003d CaSO 4 + 2H 2 O
Ca 2 SO 4 (OH) 2 + H 2 SO 4 \u003d 2CaSO 4 + 2H 2 O There are also salts containing two different cations: they are often called double salts, for example:
Oxides E X O at
- products of complete dehydration of hydroxides:Acid hydroxides
(H 2 SO 4 , H 2 CO 3) meet acidic oxides (SO 3 , CO 2), and basic hydroxides(NaOH, Ca (OH) 2) - basic oxides(Na 2 O, CaO ), and the oxidation state of the element E does not change when going from hydroxide to oxide. An example of formulas and names of oxides:Acid and basic oxides retain the salt-forming properties of the corresponding hydroxides when interacting with hydroxides of opposite properties or with each other:
N 2 O 5 + 2NaOH \u003d 2NaNO 3 + H 2 O
3CaO + 2H 3 PO 4 = Ca 3 (PO 4) 2 + 3H 2 O
La 2 O 3 + 3SO 3 \u003d La 2 (SO 4) 3
Amphoteric
(a) 2Al(OH) 3 + 3SO 3 = Al 2 (SO 4) 3 + 3H 2 O
Al 2 O 3 + 3H 2 SO 4 \u003d Al 2 (SO 4) 3 + 3H 2 O
(b) 2Al(OH) 3 + Na 2 O = 2NaAlO 2 + 3H 2 O
Al 2 O 3 + 2NaOH \u003d 2NaAlO 2 + H 2 O Thus, hydroxide and aluminum oxide in reactions (a) exhibit the properties major hydroxides and oxides, i.e. react with acidic hydroxides and oxide, forming the corresponding salt - aluminum sulfate If these reactions proceed in an aqueous solution, then the composition of the resulting salts changes, but the presence of aluminum in the cation and anion remains:
2Al(OH) 3 + 3H 2 SO 4 = 2 (SO 4) 3
Al(OH) 3 + NaOH = Na Here square brackets denote complex ions Elements that exhibit metallic and non-metallic properties in compounds are called amphoteric, these include elements of A-groups Periodic system -
Amphoteric hydroxides (if the element's oxidation state exceeds +
II ) may be in ortho - or (and) meta - form. Here are examples of amphoteric hydroxides:Amphoteric oxides do not always correspond to amphoteric hydroxides, since when trying to obtain the latter, hydrated oxides are formed, for example:
If several oxidation states correspond to an amphoteric element in compounds, then the amphotericity of the corresponding oxides and hydroxides (and, consequently, the amphotericity of the element itself) will be expressed differently. For low oxidation states, hydroxides and oxides have a predominance of basic properties, and the element itself has metallic properties, so it is almost always a part of cations. For high oxidation states, on the contrary, hydroxides and oxides have a predominance of acidic properties, and the element itself has non-metallic properties, so it is almost always included in the composition of anions. So, for manganese oxide and hydroxide (
II ) dominate the basic properties, and manganese itself is a part of cations of the type [ Mn(H 2 O) 6 ] 2+ , while manganese oxide and hydroxide ( VII ) acidic properties dominate, and manganese itself is a part of an anion of the type MnO4- . Amphoteric hydroxides with a large predominance of acidic properties are assigned formulas and names based on the model of acidic hydroxides, for example H MnVII O 4 - permanganic acid.Thus, the division of elements into metals and non-metals is conditional; between elements (
Na, K, Ca, Ba etc.) with purely metallic and elements ( F, O, N, Cl, S, C etc.) with purely non-metallic properties exists large group elements with amphoteric properties.An extensive type of inorganic complex substances is binary compounds. These include, first of all, all two-element compounds (except basic, acidic and amphoteric oxides), for example
H 2 O, KBr, H 2 S, Cs 2 (S 2), N 2 O, NH 3, HN 3, CaC 2, SiH 4 . The electropositive and electronegative components of the formulas of these compounds include individual atoms or related groups atoms of one element.Multi-element substances, in the formulas of which one of the components contains atoms of several elements that are not interconnected, as well as single-element or multi-element groups of atoms (except for hydroxides and salts), are considered as binary compounds, for example
CSO, IO 2 F 3 , SBrO 2 F, CrO(O 2) 2 , PSI 3 , (CaTi)O 3 , (FeCu)S 2 , Hg(CN) 2 , (PF 3) 2 O, VCl 2 (NH 2). Yes, CSO can be thought of as a connection CS2 in which one sulfur atom is replaced by an oxygen atom.The names of binary compounds are built according to the usual nomenclature rules, for example:
OF 2- oxygen difluoride |
K 2 O 2 - potassium peroxide |
HgCl 2 - mercury(II) chloride |
Na 2 S - sodium sulfide |
Hg 2 Cl 2 - dirtuti dichloride |
Mg 3 N 2 - magnesium nitride |
SBr2O- sulfur oxide-dibromide |
NH 4 Br - ammonium bromide |
N 2 O - dinitrogen oxide |
Pb (N 3) 2 - lead (II) azide |
NO 2 - nitrogen dioxide |
CaC2- calcium acetylenide |
For some binary compounds, special names are used, the list of which was given earlier.
The chemical properties of binary compounds are quite diverse, so they are often divided into groups according to the name of the anions, i.e. halides, chalcogenides, nitrides, carbides, hydrides, etc. are considered separately. Among binary compounds, there are also those that have some signs of other types of inorganic substances. Yes, connections
CO, NO, NO 2, and (Fe II Fe 2 III) O 4 , whose names are built using the word oxide, cannot be attributed to the type of oxides (acidic, basic, amphoteric). Carbon monoxide CO, nitrogen monoxide NO and nitrogen dioxide NO 2 do not have the corresponding acid hydroxides (although these oxides are formed by non-metals C and N ), they do not form salts, the anions of which would include C atoms II, N II and N IV. Double oxide (Fe II Fe 2 III) O 4 - oxide of diiron (III) - iron (II ) although it contains in the composition of the electropositive component atoms of the amphoteric element - iron, but in two varying degrees oxidation, as a result of which, when interacting with acid hydroxides, it forms not one, but two different salts.binary compounds such as
AgF, KBr, Na 2 S, Ba(HS) 2 , NaCN, NH 4 Cl, and Pb(N 3) 2 , are built, like salts, from real cations and anions, which is why they are called saline binary compounds (or just salts). They can be considered as products of substitution of hydrogen atoms in the compounds H F, H Cl, H Br, H 2 S, H CN and H N 3 . The latter in an aqueous solution have an acidic function, and therefore their solutions are called acids, for example H F(aqua)- hydrofluoric acid, N 2 S(aqua) - hydrosulphuric acid. However, they do not belong to the type of acid hydroxides, and their derivatives do not belong to the salts within the classification of inorganic substances.