Non-salt-forming (indifferent, indifferent) oxides CO, SiO, N 2 0, NO.

Salt-forming oxides:

Basic. Oxides whose hydrates are bases. Metal oxides with oxidation states +1 and +2 (less often +3). Examples: Na 2 O - sodium oxide, CaO - calcium oxide, CuO - copper (II) oxide, CoO - cobalt (II) oxide, Bi 2 O 3 - bismuth (III) oxide, Mn 2 O 3 - manganese (III) oxide ).

Amphoteric. Oxides whose hydrates are amphoteric hydroxides. Metal oxides with oxidation states +3 and +4 (less often +2). Examples: Al 2 O 3 - aluminum oxide, Cr 2 O 3 - chromium (III) oxide, SnO 2 - tin (IV) oxide, MnO 2 - manganese (IV) oxide, ZnO - zinc oxide, BeO - beryllium oxide.

Acidic. Oxides whose hydrates are oxygen-containing acids. Non-metal oxides. Examples: P 2 O 3 - phosphorus oxide (III), CO 2 - carbon oxide (IV), N 2 O 5 - nitrogen oxide (V), SO 3 - sulfur oxide (VI), Cl 2 O 7 - chlorine oxide ( VII). Metal oxides with oxidation states +5, +6 and +7. Examples: Sb 2 O 5 - antimony (V) oxide. CrOz - chromium (VI) oxide, MnOz - manganese (VI) oxide, Mn 2 O 7 - manganese (VII) oxide.

Change in the nature of oxides with increasing oxidation state of the metal

Physical properties

Oxides are solid, liquid and gaseous, of different colors. For example: copper (II) oxide CuO is black, calcium oxide CaO is white - solids. Sulfur oxide (VI) SO 3 is a colorless volatile liquid, and carbon monoxide (IV) CO 2 is a colorless gas under ordinary conditions.

State of aggregation

CaO, CuO, Li 2 O and other basic oxides; ZnO, Al 2 O 3, Cr 2 O 3 and other amphoteric oxides; SiO 2, P 2 O 5, CrO 3 and other acid oxides.

SO 3, Cl 2 O 7, Mn 2 O 7, etc.

Gaseous:

CO 2, SO 2, N 2 O, NO, NO 2, etc.

Solubility in water

Soluble:

a) basic oxides of alkali and alkaline earth metals;

b) almost all acid oxides (exception: SiO 2).

Insoluble:

a) all other basic oxides;

b) all amphoteric oxides

Chemical properties

1. Acid-base properties

Common properties of basic, acidic and amphoteric oxides are acid-base interactions, which are illustrated by the following diagram:

(only for oxides of alkali and alkaline earth metals) (except SiO 2).

Amphoteric oxides, having the properties of both basic and acidic oxides, interact with strong acids and alkalis:

2. Redox properties

If an element has a variable oxidation state (s.o.), then its oxides with low s. O. can exhibit reducing properties, and oxides with high c. O. - oxidative.

Examples of reactions in which oxides act as reducing agents:

Oxidation of oxides with low c. O. to oxides with high c. O. elements.

2C +2 O + O 2 = 2C +4 O 2

2S +4 O 2 + O 2 = 2S +6 O 3

2N +2 O + O 2 = 2N +4 O 2

Carbon (II) monoxide reduces metals from their oxides and hydrogen from water.

C +2 O + FeO = Fe + 2C +4 O 2

C +2 O + H 2 O = H 2 + 2C +4 O 2

Examples of reactions in which oxides act as oxidizing agents:

Reduction of oxides with high o. elements to oxides with low c. O. or to simple substances.

C +4 O 2 + C = 2C +2 O

2S +6 O 3 + H 2 S = 4S +4 O 2 + H 2 O

C +4 O 2 + Mg = C 0 + 2MgO

Cr +3 2 O 3 + 2Al = 2Cr 0 + 2Al 2 O 3

Cu +2 O + H 2 = Cu 0 + H 2 O

The use of oxides of low-active metals for the oxidation of organic substances.

Some oxides in which the element has an intermediate c. o., capable of disproportionation;

For example:

2NO 2 + 2NaOH = NaNO 2 + NaNO 3 + H 2 O

Methods of obtaining

1. Interaction of simple substances - metals and non-metals - with oxygen:

4Li + O 2 = 2Li 2 O;

2Cu + O 2 = 2CuO;

4P + 5O 2 = 2P 2 O 5

2. Dehydration of insoluble bases, amphoteric hydroxides and some acids:

Cu(OH) 2 = CuO + H 2 O

2Al(OH) 3 = Al 2 O 3 + 3H 2 O

H 2 SO 3 = SO 2 + H 2 O

H 2 SiO 3 = SiO 2 + H 2 O

3. Decomposition of some salts:

2Cu(NO 3) 2 = 2CuO + 4NO 2 + O 2

CaCO 3 = CaO + CO 2

(CuOH) 2 CO 3 = 2CuO + CO 2 + H 2 O

4. Oxidation of complex substances with oxygen:

CH 4 + 2O 2 = CO 2 + H 2 O

4FeS 2 + 11O 2 = 2Fe 2 O 3 + 8SO 2

4NH 3 + 5O 2 = 4NO + 6H 2 O

5. Reduction of oxidizing acids with metals and non-metals:

Cu + H 2 SO 4 (conc) = CuSO 4 + SO 2 + 2H 2 O

10HNO 3 (conc) + 4Ca = 4Ca(NO 3) 2 + N 2 O + 5H 2 O

2HNO 3 (diluted) + S = H 2 SO 4 + 2NO

6. Interconversions of oxides during redox reactions (see redox properties of oxides).

Oxides are complex substances consisting of two elements, one of which is oxygen. In the names of oxides, the word oxide is first indicated, then the name of the second element by which it is formed. What features do acid oxides have, and how do they differ from other types of oxides?

Oxides classification

Oxides are divided into salt-forming and non-salt-forming. Already from the name it is clear that non-salt-forming ones do not form salts. There are few such oxides: water H 2 O, oxygen fluoride OF 2 (if it is conventionally considered an oxide), carbon monoxide, or carbon monoxide (II), carbon monoxide CO; nitrogen oxides (I) and (II): N 2 O (dianitrogen oxide, laughing gas) and NO (nitrogen monoxide).

Salt-forming oxides form salts when reacting with acids or alkalis. As hydroxides they correspond to bases, amphoteric bases and oxygen-containing acids. Accordingly, they are called basic oxides (eg CaO), amphoteric oxides (Al 2 O 3) and acid oxides or acid anhydrides (CO 2).

Rice. 1. Types of oxides.

Often students are faced with the question of how to distinguish a basic oxide from an acidic one. First of all, you need to pay attention to the second element next to oxygen. Acidic oxides - contain a non-metal or transition metal (CO 2, SO 3, P 2 O 5) basic oxides - contain a metal (Na 2 O, FeO, CuO).

Basic properties of acid oxides

Acidic oxides (anhydrides) are substances that exhibit acidic properties and form oxygen-containing acids. Therefore, acidic oxides correspond to acids. For example, the acidic oxides SO 2 and SO 3 correspond to the acids H 2 SO 3 and H 2 SO 4 .

Rice. 2. Acidic oxides with corresponding acids.

Acidic oxides formed by non-metals and metals with variable valence in the highest oxidation state (for example, SO 3, Mn 2 O 7) react with basic oxides and alkalis, forming salts:

SO 3 (acid oxide) + CaO (basic oxide) = CaSO 4 (salt);

Typical reactions are the interaction of acidic oxides with bases, resulting in the formation of salt and water:

Mn 2 O 7 (acid oxide) + 2KOH (alkali) = 2KMnO 4 (salt) + H 2 O (water)

All acidic oxides, except silicon dioxide SiO 2 (silicon anhydride, silica), react with water, forming acids:

SO 3 (acid oxide) + H 2 O (water) = H 2 SO 4 (acid)

Acidic oxides are formed by interaction with oxygen of simple and complex substances (S+O 2 =SO 2), or by decomposition as a result of heating of complex substances containing oxygen - acids, insoluble bases, salts (H 2 SiO 3 = SiO 2 +H 2 O).

List of acid oxides:

*Name of acid oxide*	*Acid Oxide Formula*	*Properties of acid oxide*
Sulfur(IV) oxide	SO 2	colorless toxic gas with a pungent odor
Sulfur(VI) oxide	SO 3	highly volatile, colorless, toxic liquid
Carbon monoxide (IV)	CO2	colorless, odorless gas
Silicon(IV) oxide	SiO2	colorless crystals with strength
Phosphorus(V) oxide	P2O5	white, flammable powder with an unpleasant odor
Nitric oxide (V)	N2O5	substance consisting of colorless volatile crystals
Chlorine(VII) oxide	Cl2O7	colorless oily toxic liquid
Manganese(VII) oxide	Mn2O7	liquid with a metallic luster, which is a strong oxidizing agent.

Before we start talking about the chemical properties of oxides, we need to remember that all oxides are divided into 4 types, namely basic, acidic, amphoteric and non-salt-forming. In order to determine the type of any oxide, first of all you need to understand whether it is a metal or non-metal oxide in front of you, and then use the algorithm (you need to learn it!) presented in the following table:

Non-metal oxide	Metal oxide
1) Oxidation state of non-metal +1 or +2 Conclusion: non-salt-forming oxide Exception: Cl 2 O is not a non-salt-forming oxide	1) Metal oxidation state +1 or +2 Conclusion: metal oxide is basic Exception: BeO, ZnO and PbO are not basic oxides
2) The oxidation state is greater than or equal to +3 Conclusion: acid oxide Exception: Cl 2 O is an acidic oxide, despite the oxidation state of chlorine +1	2) Metal oxidation state +3 or +4 Conclusion: amphoteric oxide Exception: BeO, ZnO and PbO are amphoteric, despite the +2 oxidation state of the metals 3) Metal oxidation state +5, +6, +7 Conclusion: acid oxide

In addition to the types of oxides indicated above, we will also introduce two more subtypes of basic oxides, based on their chemical activity, namely active basic oxides And low-active basic oxides.

TO active basic oxides We include oxides of alkali and alkaline earth metals (all elements of groups IA and IIA, except hydrogen H, beryllium Be and magnesium Mg). For example, Na 2 O, CaO, Rb 2 O, SrO, etc.
TO low-active basic oxides we will include all the main oxides that are not included in the list active basic oxides. For example, FeO, CuO, CrO, etc.

It is logical to assume that active basic oxides often enter into reactions that low-active ones do not.
It should be noted that despite the fact that water is actually an oxide of a non-metal (H 2 O), its properties are usually considered in isolation from the properties of other oxides. This is due to its specifically huge distribution in the world around us, and therefore in most cases water is not a reagent, but a medium in which countless chemical reactions can take place. However, it often takes a direct part in various transformations; in particular, some groups of oxides react with it.

Which oxides react with water?

Of all the oxides with water react only:
1) all active basic oxides (oxides of alkali metal and alkali metal);
2) all acid oxides, except silicon dioxide (SiO 2);

those. From the above it follows that with water exactly don't react:
1) all low-active basic oxides;
2) all amphoteric oxides;
3) non-salt-forming oxides (NO, N 2 O, CO, SiO).

The ability to determine which oxides can react with water even without the ability to write the corresponding reaction equations already allows you to get points for some questions in the test part of the Unified State Exam.

Now let's figure out how certain oxides react with water, i.e. Let's learn to write the corresponding reaction equations.

Active basic oxides, reacting with water, form their corresponding hydroxides. Recall that the corresponding metal oxide is a hydroxide that contains the metal in the same oxidation state as the oxide. So, for example, when the active basic oxides K +1 2 O and Ba +2 O react with water, their corresponding hydroxides K +1 OH and Ba +2 (OH) 2 are formed:

K2O + H2O = 2KOH– potassium hydroxide

BaO + H 2 O = Ba(OH) 2– barium hydroxide

All hydroxides corresponding to active basic oxides (alkali metal and alkaline metal oxides) belong to alkalis. Alkalis are all metal hydroxides that are highly soluble in water, as well as slightly soluble calcium hydroxide Ca(OH) 2 (as an exception).

The interaction of acidic oxides with water, as well as the reaction of active basic oxides with water, leads to the formation of the corresponding hydroxides. Only in the case of acidic oxides do they correspond not to basic ones, but to acidic hydroxides, more often called oxygen-containing acids. Let us recall that the corresponding acidic oxide is an oxygen-containing acid that contains an acid-forming element in the same oxidation state as in the oxide.

Thus, if we, for example, want to write down the equation for the interaction of the acidic oxide SO 3 with water, first of all we must remember the main sulfur-containing acids studied in the school curriculum. These are hydrogen sulfide H 2 S, sulfurous H 2 SO 3 and sulfuric H 2 SO 4 acids. Hydrogen sulfide acid H 2 S, as is easy to see, is not oxygen-containing, so its formation during the interaction of SO 3 with water can be immediately excluded. Of the acids H 2 SO 3 and H 2 SO 4, only sulfuric acid H 2 SO 4 contains sulfur in the oxidation state +6, as in SO 3 oxide. Therefore, it is precisely this that will be formed in the reaction of SO 3 with water:

H 2 O + SO 3 = H 2 SO 4

Similarly, the oxide N 2 O 5, containing nitrogen in the oxidation state +5, reacting with water, forms nitric acid HNO 3, but in no case nitrous HNO 2, since in nitric acid the oxidation state of nitrogen is the same as in N 2 O 5 , is equal to +5, and in nitrogen - +3:

N +5 2 O 5 + H 2 O = 2HN +5 O 3

Interaction of oxides with each other

First of all, you need to clearly understand the fact that among salt-forming oxides (acidic, basic, amphoteric), reactions almost never occur between oxides of the same class, i.e. In the vast majority of cases, interaction is impossible:

1) basic oxide + basic oxide ≠

2) acid oxide + acid oxide ≠

3) amphoteric oxide + amphoteric oxide ≠

While interaction is almost always possible between oxides belonging to different types, i.e. almost always are leaking reactions between:

1) basic oxide and acidic oxide;

2) amphoteric oxide and acid oxide;

3) amphoteric oxide and basic oxide.

As a result of all such interactions, the product is always average (normal) salt.

Let us consider all these pairs of interactions in more detail.

As a result of the interaction:

Me x O y + acid oxide, where Me x O y – metal oxide (basic or amphoteric)

a salt is formed consisting of the metal cation Me (from the initial Me x O y) and the acid residue of the acid corresponding to the acid oxide.

As an example, let’s try to write down the interaction equations for the following pairs of reagents:

Na 2 O + P 2 O 5 And Al 2 O 3 + SO 3

In the first pair of reagents we see a basic oxide (Na 2 O) and an acidic oxide (P 2 O 5). In the second - amphoteric oxide (Al 2 O 3) and acidic oxide (SO 3).

As already mentioned, as a result of the interaction of a basic/amphoteric oxide with an acidic one, a salt is formed, consisting of a metal cation (from the original basic/amphoteric oxide) and an acidic residue of the acid corresponding to the original acidic oxide.

Thus, the interaction of Na 2 O and P 2 O 5 should form a salt consisting of Na + cations (from Na 2 O) and the acidic residue PO 4 3-, since the oxide P +5 2 O 5 corresponds to acid H 3 P +5 O4. Those. As a result of this interaction, sodium phosphate is formed:

3Na 2 O + P 2 O 5 = 2Na 3 PO 4- sodium phosphate

In turn, the interaction of Al 2 O 3 and SO 3 should form a salt consisting of Al 3+ cations (from Al 2 O 3) and the acidic residue SO 4 2-, since the oxide S +6 O 3 corresponds to acid H 2 S +6 O4. Thus, as a result of this reaction, aluminum sulfate is obtained:

Al 2 O 3 + 3SO 3 = Al 2 (SO 4) 3- aluminum sulfate

More specific is the interaction between amphoteric and basic oxides. These reactions are carried out at high temperatures, and their occurrence is possible due to the fact that the amphoteric oxide actually takes on the role of an acidic one. As a result of this interaction, a salt of a specific composition is formed, consisting of a metal cation forming the original basic oxide and an “acid residue”/anion, which includes the metal from the amphoteric oxide. The general formula of such an “acid residue”/anion can be written as MeO 2 x - , where Me is a metal from an amphoteric oxide, and x = 2 in the case of amphoteric oxides with a general formula of the form Me + 2 O (ZnO, BeO, PbO) and x = 1 – for amphoteric oxides with a general formula of the form Me +3 2 O 3 (for example, Al 2 O 3, Cr 2 O 3 and Fe 2 O 3).

Let's try to write down the interaction equations as an example

ZnO + Na 2 O And Al 2 O 3 + BaO

In the first case, ZnO is an amphoteric oxide with the general formula Me +2 O, and Na 2 O is a typical basic oxide. According to the above, as a result of their interaction, a salt should be formed, consisting of a metal cation forming a basic oxide, i.e. in our case, Na + (from Na 2 O) and the “acid residue”/anion with the formula ZnO 2 2-, since the amphoteric oxide has a general formula of the form Me + 2 O. Thus, the formula of the resulting salt, subject to the condition of electrical neutrality of one of its structural units (“molecules”) will have the form Na 2 ZnO 2:

ZnO + Na 2 O = t o=> Na 2 ZnO 2

In the case of an interacting pair of reagents Al 2 O 3 and BaO, the first substance is an amphoteric oxide with the general formula Me + 3 2 O 3, and the second is a typical basic oxide. In this case, a salt is formed containing a metal cation from the main oxide, i.e. Ba 2+ (from BaO) and the “acid residue”/anion AlO 2 - . Those. the formula of the resulting salt, subject to the condition of electrical neutrality of one of its structural units (“molecules”), will have the form Ba(AlO 2) 2, and the interaction equation itself will be written as:

Al 2 O 3 + BaO = t o=> Ba(AlO 2) 2

As we wrote above, the reaction almost always occurs:

Me x O y + acid oxide,

where Me x O y is either a basic or amphoteric metal oxide.

However, there are two "finicky" acid oxides to remember - carbon dioxide (CO 2) and sulfur dioxide (SO 2). Their “fastidiousness” lies in the fact that despite their obvious acidic properties, the activity of CO 2 and SO 2 is not enough for them to interact with low-active basic and amphoteric oxides. Of the metal oxides, they react only with active basic oxides(oxides of alkali metal and alkali metal). For example, Na 2 O and BaO, being active basic oxides, can react with them:

CO 2 + Na 2 O = Na 2 CO 3

SO 2 + BaO = BaSO 3

While the oxides CuO and Al 2 O 3, which are not related to active basic oxides, do not react with CO 2 and SO 2:

CO 2 + CuO ≠

CO 2 + Al 2 O 3 ≠

SO 2 + CuO ≠

SO 2 + Al 2 O 3 ≠

Interaction of oxides with acids

Basic and amphoteric oxides react with acids. In this case, salts and water are formed:

FeO + H 2 SO 4 = FeSO 4 + H 2 O

Non-salt-forming oxides do not react with acids at all, and acidic oxides do not react with acids in most cases.

When does an acidic oxide react with an acid?

When solving the multiple-choice part of the Unified State Exam, you should conditionally assume that acidic oxides do not react with either acidic oxides or acids, except in the following cases:

1) silicon dioxide, being an acidic oxide, reacts with hydrofluoric acid, dissolving in it. In particular, thanks to this reaction, glass can be dissolved in hydrofluoric acid. In the case of excess HF, the reaction equation has the form:

SiO 2 + 6HF = H 2 + 2H 2 O,

and in case of HF deficiency:

SiO 2 + 4HF = SiF 4 + 2H 2 O

2) SO 2, being an acidic oxide, easily reacts with hydrosulfide acid H 2 S like co-proportionation:

S +4 O 2 + 2H 2 S -2 = 3S 0 + 2H 2 O

3) Phosphorus (III) oxide P 2 O 3 can react with oxidizing acids, which include concentrated sulfuric acid and nitric acid of any concentration. In this case, the oxidation state of phosphorus increases from +3 to +5:

P2O3	+	2H2SO4	+	H2O	=t o=>	2SO 2	+	2H3PO4
		(conc.)

3 P2O3	+	4HNO3	+	7 H2O	=t o=>	4NO	+	6 H3PO4
		(detailed)

2HNO3	+	3SO 2	+	2H2O	*=t o=>*	3H2SO4	+	2NO
(detailed)

Interaction of oxides with metal hydroxides

Acidic oxides react with metal hydroxides, both basic and amphoteric. This produces a salt consisting of a metal cation (from the original metal hydroxide) and an acid residue corresponding to the acid oxide.

SO 3 + 2NaOH = Na 2 SO 4 + H 2 O

Acidic oxides, which correspond to polybasic acids, can form both normal and acid salts with alkalis:

CO 2 + 2NaOH = Na 2 CO 3 + H 2 O

CO 2 + NaOH = NaHCO 3

P 2 O 5 + 6KOH = 2K 3 PO 4 + 3H 2 O

P 2 O 5 + 4KOH = 2K 2 HPO 4 + H 2 O

P 2 O 5 + 2KOH + H 2 O = 2KH 2 PO 4

“Finicky” oxides CO 2 and SO 2, the activity of which, as already mentioned, is not enough for their reaction with low-active basic and amphoteric oxides, nevertheless, react with most of the corresponding metal hydroxides. More precisely, carbon dioxide and sulfur dioxide react with insoluble hydroxides in the form of their suspension in water. In this case, only the basic O natural salts called hydroxycarbonates and hydroxosulfites, and the formation of intermediate (normal) salts is impossible:

2Zn(OH) 2 + CO 2 = (ZnOH) 2 CO 3 + H 2 O(in solution)

2Cu(OH) 2 + CO 2 = (CuOH) 2 CO 3 + H 2 O(in solution)

However, carbon dioxide and sulfur dioxide do not react at all with metal hydroxides in the oxidation state +3, for example, such as Al(OH) 3, Cr(OH) 3, etc.

It should also be noted that silicon dioxide (SiO 2) is particularly inert, most often found in nature in the form of ordinary sand. This oxide is acidic, but among metal hydroxides it is capable of reacting only with concentrated (50-60%) solutions of alkalis, as well as with pure (solid) alkalis during fusion. In this case, silicates are formed:

2NaOH + SiO 2 = t o=> Na 2 SiO 3 + H 2 O

Amphoteric oxides from metal hydroxides react only with alkalis (hydroxides of alkali and alkaline earth metals). In this case, when the reaction is carried out in aqueous solutions, soluble complex salts are formed:

ZnO + 2NaOH + H 2 O = Na 2- sodium tetrahydroxozincate

BeO + 2NaOH + H 2 O = Na 2- sodium tetrahydroxoberyllate

Al 2 O 3 + 2NaOH + 3H 2 O = 2Na- sodium tetrahydroxyaluminate

Cr 2 O 3 + 6NaOH + 3H 2 O = 2Na 3- sodium hexahydroxochromate (III)

And when these same amphoteric oxides are fused with alkalis, salts are obtained consisting of an alkali or alkaline earth metal cation and an anion of the type MeO 2 x -, where x= 2 in the case of amphoteric oxide type Me +2 O and x= 1 for an amphoteric oxide of the form Me 2 +2 O 3:

ZnO + 2NaOH = t o=> Na 2 ZnO 2 + H 2 O

BeO + 2NaOH = t o=> Na 2 BeO 2 + H 2 O

Al 2 O 3 + 2NaOH = t o=> 2NaAlO 2 + H 2 O

Cr 2 O 3 + 2NaOH = t o=> 2NaCrO 2 + H 2 O

Fe 2 O 3 + 2NaOH = t o=> 2NaFeO 2 + H 2 O

It should be noted that salts obtained by fusing amphoteric oxides with solid alkalis can be easily obtained from solutions of the corresponding complex salts by evaporation and subsequent calcination:

Na 2 = t o=> Na 2 ZnO 2 + 2H 2 O

Na = t o=> NaAlO 2 + 2H 2 O

Interaction of oxides with medium salts

Most often, medium salts do not react with oxides.

However, you should learn the following exceptions to this rule, which are often encountered in the exam.

One of these exceptions is that amphoteric oxides, as well as silicon dioxide (SiO 2), when fused with sulfites and carbonates, displace sulfur dioxide (SO 2) and carbon dioxide (CO 2) gases from the latter, respectively. For example:

Al 2 O 3 + Na 2 CO 3 = t o=> 2NaAlO 2 + CO 2

SiO 2 + K 2 SO 3 = t o=> K 2 SiO 3 + SO 2

Also, reactions of oxides with salts can conditionally include the interaction of sulfur dioxide and carbon dioxide with aqueous solutions or suspensions of the corresponding salts - sulfites and carbonates, leading to the formation of acid salts:

Na 2 CO 3 + CO 2 + H 2 O = 2NaHCO 3

CaCO 3 + CO 2 + H 2 O = Ca(HCO 3) 2

Also, sulfur dioxide, when passed through aqueous solutions or suspensions of carbonates, displaces carbon dioxide from them due to the fact that sulfurous acid is a stronger and more stable acid than carbonic acid:

K 2 CO 3 + SO 2 = K 2 SO 3 + CO 2

ORR involving oxides

Reduction of metal and non-metal oxides

Just as metals can react with solutions of salts of less active metals, displacing the latter in free form, metal oxides when heated are also able to react with more active metals.

Let us recall that the activity of metals can be compared either using the activity series of metals, or, if one or two metals are not in the activity series, by their position relative to each other in the periodic table: the lower and to the left the metal, the more active it is. It is also useful to remember that any metal from the AHM and ALP family will always be more active than a metal that is not a representative of ALM or ALP.

In particular, the aluminothermy method, used in industry to obtain such difficult-to-reduce metals as chromium and vanadium, is based on the interaction of a metal with the oxide of a less active metal:

Cr 2 O 3 + 2Al = t o=> Al 2 O 3 + 2Cr

During the aluminothermic process, a colossal amount of heat is generated, and the temperature of the reaction mixture can reach more than 2000 o C.

Also, the oxides of almost all metals located in the activity series to the right of aluminum can be reduced to free metals by hydrogen (H 2), carbon (C) and carbon monoxide (CO) when heated. For example:

Fe 2 O 3 + 3CO = t o=> 2Fe + 3CO 2

CuO+C= t o=> Cu + CO

FeO + H2 = t o=> Fe + H 2 O

It should be noted that if the metal can have several states of oxidation, if there is a lack of the reducing agent used, incomplete reduction of the oxides is also possible. For example:

Fe 2 O 3 + CO =t o=> 2FeO + CO 2

4CuO + C = t o=> 2Cu 2 O + CO 2

Oxides of active metals (alkali, alkaline earth, magnesium and aluminum) with hydrogen and carbon monoxide don't react.

However, oxides of active metals react with carbon, but differently than oxides of less active metals.

Within the framework of the Unified State Examination program, in order not to be confused, it should be assumed that as a result of the reaction of oxides of active metals (up to Al inclusive) with carbon, the formation of free alkali metal, alkali metal, Mg, and Al is impossible. In such cases, metal carbide and carbon monoxide are formed. For example:

2Al 2 O 3 + 9C = t o=> Al 4 C 3 + 6CO

CaO + 3C = t o=> CaC 2 + CO

Oxides of nonmetals can often be reduced by metals to free nonmetals. For example, when heated, oxides of carbon and silicon react with alkali, alkaline earth metals and magnesium:

CO2 + 2Mg = t o=> 2MgO + C

SiO2 + 2Mg = t o=>Si + 2MgO

With an excess of magnesium, the latter interaction can also lead to the formation magnesium silicide Mg 2 Si:

SiO2 + 4Mg = t o=> Mg 2 Si + 2 MgO

Nitrogen oxides can be reduced relatively easily even with less active metals, such as zinc or copper:

Zn + 2NO = t o=> ZnO + N 2

NO 2 + 2Cu = t o=> 2CuO + N 2

Interaction of oxides with oxygen

In order to be able to answer the question of whether any oxide reacts with oxygen (O 2) in the tasks of the real Unified State Examination, you first need to remember that oxides that can react with oxygen (from those that you may come across in the exam itself) can form only chemical elements from the list:

Oxides of any other chemical elements found in the real Unified State Exam react with oxygen will not (!).

For a more visual and convenient memorization of the list of elements listed above, in my opinion, the following illustration is convenient:

All chemical elements capable of forming oxides that react with oxygen (from those encountered on the exam)

First of all, among the listed elements, nitrogen N should be considered, because the ratio of its oxides to oxygen differs markedly from the oxides of other elements in the above list.

It should be clearly remembered that nitrogen can form five oxides in total, namely:

Of all nitrogen oxides, it can react with oxygen only NO. This reaction occurs very easily when NO is mixed with both pure oxygen and air. In this case, a rapid change in the color of the gas from colorless (NO) to brown (NO 2) is observed:

2NO	+	O2	=	2NO 2
colorless				brown

In order to answer the question - does any oxide of any other of the chemical elements listed above react with oxygen (i.e. WITH,Si, P, S, Cu, Mn, Fe, Cr) — First of all, you need to remember them basic oxidation state (CO). Here they are :

Next, you need to remember the fact that of the possible oxides of the above chemical elements, only those that contain the element in the minimum oxidation state among those indicated above will react with oxygen. In this case, the oxidation state of the element increases to the nearest positive value possible:

element	Its oxide ratioto oxygen
WITH	The minimum among the main positive oxidation states of carbon is equal to +2 , and the closest positive one is +4 . Thus, only CO reacts with oxygen from the oxides C +2 O and C +4 O 2. In this case the reaction occurs: *2C +2 O + O 2 = t o=> 2C +4 O 2* CO 2 + O 2 ≠- the reaction is impossible in principle, because +4 – the highest degree of carbon oxidation.
Si	The minimum among the main positive oxidation states of silicon is +2, and the closest positive one to it is +4. Thus, only SiO reacts with oxygen from the oxides Si +2 O and Si +4 O 2. Due to some features of the oxides SiO and SiO 2, oxidation of only part of the silicon atoms in the oxide Si + 2 O is possible. as a result of its interaction with oxygen, a mixed oxide is formed containing both silicon in the +2 oxidation state and silicon in the +4 oxidation state, namely Si 2 O 3 (Si +2 O·Si +4 O 2): *4Si +2 O + O 2 = t o=> 2Si +2 ,+4 2 O 3 (Si +2 O·Si +4 O 2)* SiO 2 + O 2 ≠- the reaction is impossible in principle, because +4 – the highest oxidation state of silicon.
P	The minimum among the main positive oxidation states of phosphorus is +3, and the closest positive one to it is +5. Thus, only P 2 O 3 reacts with oxygen from the oxides P +3 2 O 3 and P +5 2 O 5. In this case, the reaction of additional oxidation of phosphorus with oxygen occurs from the oxidation state +3 to the oxidation state +5: *P +3 2 O 3 + O 2 = t o=> P +5 2 O 5* P +5 2 O 5 + O 2 ≠- the reaction is impossible in principle, because +5 – the highest oxidation state of phosphorus.
S	The minimum among the main positive oxidation states of sulfur is +4, and the closest positive oxidation state to it is +6. Thus, only SO 2 reacts with oxygen from the oxides S +4 O 2 and S +6 O 3 . In this case the reaction occurs: *2S +4 O 2 + O 2 = t o=> 2S +6 O 3* 2S +6 O 3 + O 2 ≠- the reaction is impossible in principle, because +6 – the highest degree of sulfur oxidation.
Cu	The minimum among positive oxidation states of copper is +1, and the closest value to it is positive (and the only one) +2. Thus, only Cu 2 O reacts with oxygen from the oxides Cu +1 2 O, Cu +2 O. In this case, the reaction occurs: *2Cu +1 2 O + O 2 = t o=> 4Cu +2 O* CuO + O 2 ≠- the reaction is impossible in principle, because +2 – the highest oxidation state of copper.
Cr	The minimum among the main positive oxidation states of chromium is +2, and the positive one closest to it is +3. Thus, only CrO reacts with oxygen from the oxides Cr +2 O, Cr +3 2 O 3 and Cr +6 O 3, while being oxidized by oxygen to the next (possible) positive oxidation state, i.e. +3: *4Cr +2 O + O 2 = t o=> 2Cr +3 2 O 3* Cr +3 2 O 3 + O 2 ≠- the reaction does not proceed, despite the fact that chromium oxide exists and in an oxidation state greater than +3 (Cr +6 O 3). The impossibility of this reaction occurring is due to the fact that the heating required for its hypothetical implementation greatly exceeds the decomposition temperature of CrO 3 oxide. Cr +6 O 3 + O 2 ≠ — this reaction cannot proceed in principle, because +6 is the highest oxidation state of chromium.
Mn	The minimum among the main positive oxidation states of manganese is +2, and the closest positive one is +4. Thus, from the possible oxides Mn +2 O, Mn +4 O 2, Mn +6 O 3 and Mn +7 2 O 7, only MnO reacts with oxygen, while being oxidized by oxygen to the next (possible) positive oxidation state, t .e. +4: *2Mn +2 O + O 2 = t o=> 2Mn +4 O 2* while: Mn +4 O 2 + O 2 ≠ And Mn +6 O 3 + O 2 ≠- reactions do not occur, despite the fact that there is manganese oxide Mn 2 O 7 containing Mn in an oxidation state greater than +4 and +6. This is due to the fact that required for further hypothetical oxidation of Mn oxides +4 O2 and Mn +6 O 3 heating significantly exceeds the decomposition temperature of the resulting oxides MnO 3 and Mn 2 O 7. Mn +7 2 O 7 + O 2 ≠- this reaction is impossible in principle, because +7 – the highest oxidation state of manganese.
Fe	The minimum among the main positive oxidation states of iron is equal to +2 , and the closest one among the possible ones is +3 . Despite the fact that for iron there is an oxidation state of +6, the acidic oxide FeO 3, however, as well as the corresponding “iron” acid does not exist. Thus, of the iron oxides, only those oxides that contain Fe in the +2 oxidation state can react with oxygen. It's either Fe oxide +2 O, or mixed iron oxide Fe +2 ,+3 3 O 4 (iron scale): *4Fe +2 O + O 2 = t o=> 2Fe +3 2 O 3* or *6Fe +2 O + O 2 = t o=> 2Fe +2,+3 3 O 4* mixed Fe oxide +2,+3 3 O 4 can be oxidized to Fe +3 2 O 3: *4Fe +2,+3 3 O 4 + O 2 = t o=> 6Fe +3 2 O 3* Fe +3 2 O 3 + O 2 ≠ - this reaction is impossible in principle, because There are no oxides containing iron in an oxidation state higher than +3.

Chemical properties of the main classes of inorganic compounds

Acidic oxides

Acidic oxide + water = acid (exception - SiO 2)
SO 3 + H 2 O = H 2 SO 4
Cl 2 O 7 + H 2 O = 2HClO 4
Acidic oxide + alkali = salt + water
SO 2 + 2NaOH = Na 2 SO 3 + H 2 O
P 2 O 5 + 6KOH = 2K 3 PO 4 + 3H 2 O
Acidic oxide + basic oxide = salt
CO 2 + BaO = BaCO 3
SiO 2 + K 2 O = K 2 SiO 3
Basic oxides
1. Basic oxide + water = alkali (alkali and alkaline earth metal oxides react)
  CaO + H 2 O = Ca(OH) 2
  Na 2 O + H 2 O = 2NaOH
2. Basic oxide + acid = salt + water
  CuO + 2HCl = CuCl 2 + H 2 O
  3K 2 O + 2H 3 PO 4 = 2K 3 PO 4 + 3H 2 O
3. Basic oxide + acidic oxide = salt
  MgO + CO 2 = MgCO 3
  Na 2 O + N 2 O 5 = 2NaNO 3
  Amphoteric oxides
  1. Amphoteric oxide + acid = salt + water
    Al 2 O 3 + 6HCl = 2AlCl 3 + 3H 2 O
    ZnO + H 2 SO 4 = ZnSO 4 + H 2 O
  2. Amphoteric oxide + alkali = salt (+ water)
    ZnO + 2KOH = K 2 ZnO 2 + H 2 O (More correct: ZnO + 2KOH + H 2 O = K 2)
    Al 2 O 3 + 2NaOH = 2NaAlO 2 + H 2 O (More correct: Al 2 O 3 + 2NaOH + 3H 2 O = 2Na)
  3. Amphoteric oxide + acidic oxide = salt
    ZnO + CO 2 = ZnCO 3
  4. Amphoteric oxide + basic oxide = salt (if fused)
    ZnO + Na 2 O = Na 2 ZnO 2
    Al 2 O 3 + K 2 O = 2KAlO 2
    Cr 2 O 3 + CaO = Ca(CrO 2) 2
    Acids
    1. Acid + basic oxide = salt + water
      2HNO 3 + CuO = Cu(NO 3) 2 + H 2 O
      3H 2 SO 4 + Fe 2 O 3 = Fe 2 (SO 4) 3 + 3H 2 O
    2. Acid + amphoteric oxide = salt + water
      3H 2 SO 4 + Cr 2 O 3 = Cr 2 (SO 4) 3 + 3H 2 O
      2HBr + ZnO = ZnBr 2 + H 2 O
    3. Acid + base = salt + water
      H 2 SiO 3 + 2KOH = K 2 SiO 3 + 2H 2 O
      2HBr + Ni(OH) 2 = NiBr 2 + 2H 2 O
    4. Acid + amphoteric hydroxide = salt + water
      3HCl + Cr(OH) 3 = CrCl 3 + 3H 2 O
      2HNO 3 + Zn(OH) 2 = Zn(NO 3) 2 + 2H 2 O
    5. Strong acid + salt of weak acid = weak acid + salt of strong acid
      2HBr + CaCO 3 = CaBr 2 + H 2 O + CO 2
      H 2 S + K 2 SiO 3 = K 2 S + H 2 SiO 3
    6. Acid + metal (located in the voltage series to the left of hydrogen) = salt + hydrogen
      2HCl + Zn = ZnCl 2 + H 2
      H 2 SO 4 (diluted) + Fe = FeSO 4 + H 2
      Important: oxidizing acids (HNO 3, conc. H 2 SO 4) react with metals differently.
    Amphoteric hydroxides
    1. Amphoteric hydroxide + acid = salt + water
      2Al(OH) 3 + 3H 2 SO 4 = Al 2 (SO 4) 3 + 6H 2 O
      Be(OH) 2 + 2HCl = BeCl 2 + 2H 2 O
    2. Amphoteric hydroxide + alkali = salt + water (when fused)
      Zn(OH) 2 + 2NaOH = Na 2 ZnO 2 + 2H 2 O
      Al(OH) 3 + NaOH = NaAlO 2 + 2H 2 O
    3. Amphoteric hydroxide + alkali = salt (in aqueous solution)
      Zn(OH) 2 + 2NaOH = Na 2
      Sn(OH) 2 + 2NaOH = Na 2
      Be(OH) 2 + 2NaOH = Na 2
      Al(OH) 3 + NaOH = Na
      Cr(OH) 3 + 3NaOH = Na 3
      Alkalis
      1. Alkali + acid oxide = salt + water
        Ba(OH) 2 + N 2 O 5 = Ba(NO 3) 2 + H 2 O
        2NaOH + CO 2 = Na 2 CO 3 + H 2 O
      2. Alkali + acid = salt + water
        3KOH + H3PO4 = K3PO4 + 3H2O
        Ba(OH) 2 + 2HNO 3 = Ba(NO 3) 2 + 2H 2 O
      3. Alkali + amphoteric oxide = salt + water
        2NaOH + ZnO = Na 2 ZnO 2 + H 2 O (More correct: 2NaOH + ZnO + H 2 O = Na 2)
      4. Alkali + amphoteric hydroxide = salt (in aqueous solution)
        2NaOH + Zn(OH) 2 = Na 2
        NaOH + Al(OH) 3 = Na
      5. Alkali + soluble salt = insoluble base + salt
        Ca(OH) 2 + Cu(NO 3) 2 = Cu(OH) 2 + Ca(NO 3) 2
        3KOH + FeCl 3 = Fe(OH) 3 + 3KCl
      6. Alkali + metal (Al, Zn) + water = salt + hydrogen
        2NaOH + Zn + 2H 2 O = Na 2 + H 2
        2KOH + 2Al + 6H 2 O = 2K + 3H 2
        Salts
        Salt of a weak acid + strong acid = salt of a strong acid + weak acid
        Na 2 SiO 3 + 2HNO 3 = 2NaNO 3 + H 2 SiO 3
        BaCO 3 + 2HCl = BaCl 2 + H 2 O + CO 2 (H 2 CO 3)
        Soluble salt + soluble salt = insoluble salt + salt
        Pb(NO 3) 2 + K 2 S = PbS + 2KNO 3
        СaCl 2 + Na 2 CO 3 = CaCO 3 + 2NaCl
        Soluble salt + alkali = salt + insoluble base
        Cu(NO 3) 2 + 2NaOH = 2NaNO 3 + Cu(OH) 2
        2FeCl 3 + 3Ba(OH) 2 = 3BaCl 2 + 2Fe(OH) 3
        Soluble metal salt (*) + metal (**) = metal salt (**) + metal (*)
        Zn + CuSO 4 = ZnSO 4 + Cu
        Cu + 2AgNO 3 = Cu(NO 3) 2 + 2Ag
        Important: 1) the metal (**) must be in the voltage series to the left of the metal (*), 2) the metal (**) must NOT react with water.
        You may also be interested in other sections of the chemistry reference book:

Oxides formula necessary to be able to solve problems and understand possible combinations of chemical elements. General formula of oxides- E x O y. Oxygen has the second highest electronegativity value after fluorine, which is the reason that most compounds of chemical elements with oxygen are oxides.

By oxide classifications, salt-forming oxides are those oxides that can react with acids or bases with the possibility of the appearance of the corresponding salt and water. Salt-forming oxides are called:

Basic oxides, often formed from metals with an oxidation state of +1, +2. They can react with acids, acid oxides, amphoteric oxides, and water (only oxides of alkali and alkaline earth metals). The basic oxide element becomes a cation in the resulting salt. Na 2 O, CaO, MgO, CuO.

Basic oxide + strong acid → salt + water: CuO + H 2 SO 4 → CuSO 4 + H 2 O
Strong basic oxide + water → hydroxide: CaO + H 2 O → Ca(OH) 2
Strongly basic oxide + acidic oxide → salt: CaO + Mn 2 O 7 → Ca(MnO 4) 2
Basic oxide + hydrogen → metal + water: CuO + H 2 → Cu + H 2 O

Note: the metal is less reactive than aluminum.

Acidic oxides- oxides of non-metals and metals in the oxidation state +5 - +7. Can react with water, alkalis, basic oxides, amphoteric oxides. The acid oxide element is part of the anion of the resulting salt. Mn 2 O 7, CrO 3, SO 3, N 2 O 5.

Acidic oxide + water → acid: SO 3 + H 2 O → H 2 SO 4. Some oxides, for example SiO 2, cannot react with water, so their acids are obtained indirectly.
Acidic oxide + basic oxide → salt: CO 2 + CaO → CaCO 3
Acid oxide + base → salt + water: SO 2 + 2NaOH → Na 2 SO 3 + H 2 O. If the acid oxide is an anhydride of a polybasic acid, the formation of acid or medium salts is possible: Ca(OH) 2 + CO 2 → CaCO 3 ↓ + H 2 O, CaCO 3 + H 2 O + CO 2 → Ca(HCO 3) 2
Non-volatile oxide + salt 1 → salt 2 + volatile oxide: SiO 2 + Na 2 CO 3 → Na 2 SiO 3 + CO 2
Acid anhydride 1 + anhydrous oxygenated acid 2 → Acid anhydride 2 + anhydrous oxygenated acid 1: 2P 2 O 5 + 4HClO 4 → 4HPO 3 + 2Cl 2 O 7

Amphoteric oxides, form metals with an oxidation state from +3 to +5 (amphoteric oxides also include BeO, ZnO, PbO, SnO). Reacts with acids, alkalis, acidic and basic oxides.

When interacting with a strong acid or acid oxide, they exhibit basic properties: ZnO + 2HCl → ZnCl 2 + H 2 O

When interacting with a strong base or basic oxide, they exhibit acid properties:

ZnO + 2KOH + H 2 O → K 2 (in aqueous solution).
ZnO + 2KOH → K 2 ZnO 2 (when fused).

Non-salt-forming oxides They do not react with either acids or bases, which means they do not form salts. N 2 O, NO, CO, SiO.

In accordance with the IUPAC nomenclature, the names of oxides are composed of the word oxide and the name of the second chemical element (with lower electronegativity) in the genitive case:

Calcium oxide - CaO.

If an element can form several oxides, then their names should indicate the oxidation state of the element:

Fe 2 O 3 - iron (III) oxide;
MnO 2 - manganese (IV) oxide.

You can use Latin prefixes to denote the number of atoms of elements that are included in the oxide molecule:

Na 2 O - disodium oxide;
CO - carbon monoxide;
CO 2 - carbon dioxide.

The trivial names of some oxides are also often used:

Names of oxides.

Oxide formula	Systematic name	Trivial name
		Carbon monoxide
		Carbon dioxide
	Magnesium oxide	Magnesia
	Calcium oxide	Quicklime
	Iron(II) oxide	Iron oxide
Fe2O3	Iron(III) oxide	Iron oxide
	Phosphorus(V) oxide	Phosphoric anhydride
H 2 O 2	Hydrogen peroxide
SO 2	Sulfur(IV) oxide
Ag2O	Silver(I) oxide
Cu2O3	Copper(III) oxide	dicopper trioxide
CuO	Copper(II) oxide	copper oxide
Cu2O	Copper(I) oxide	Cuprous oxide, cuprous oxide, dicopper oxide

Create a formula for the oxides.

At compiling oxide formulas The element whose oxidation state is + is placed first, and the element with a negative oxidation state is placed second. For oxides this is always oxygen.

Subsequent steps to compile the oxide formula:

1. Arrange the oxidation states (oxidation state) for each atom. Oxygen in oxides always has an oxidation state of -2 (minus two).

2. In order to correctly find out the oxidation state of the second element, you need to look at the table of possible oxidation states of some elements.

When compiling names of substances, I most often use Russian names of elements, for example, dioxygen, xenon difluoride, potassium selenate. Sometimes for some elements the roots of their Latin names are introduced into derivative terms:

Names of elements in the composition of oxide formulas.

Ag - argent
As - ars, arsen	Ni - nikkol
	O - ox, oxygen
C - carb, carbon


H - hydr, hydrogen	Si - seal, silic, silic
Hg - mercury
Mn - mangan

For example: carbonate, manganate, oxide, sulfide, silicate.

The names of simple substances consist of one word - the name of the chemical element with a numerical prefix, for example:

The following numerical prefixes are used:

Numerical prefixes in the preparation of oxide formulas.

An indefinite number is indicated by a numeric prefix n- poly.

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 acidic residues (a dash means that the hydroxide is not known in free form or in an acidic aqueous solution):

Formulas and proper names of common acid hydroxides and their acid residues.

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
	B 4 O 7 2- - tetraborate
	ВiО 3 - - bismuthate
HBrO - bromide	BrO - - hypobromite
HBrO 3 - brominated	BrO 3 - - bromate
H 2 CO 3 - coal	CO 3 2- - carbonate
HClO - hypochlorous	ClO- - hypochlorite
HClO 2 - chloride	ClO2 - - chlorite
HClO 3 - chloric	ClO3 - - chlorate
HClO 4 - chlorine	ClO4 - - perchlorate
H 2 CrO 4 - chrome	CrO 4 2- - chromate
	НCrO 4 - - hydrochromate
H 2 Cr 2 O 7 - dichromic	Cr2O72- - dichromate
	FeO 4 2- - ferrate
HIO 3 - iodine	IO 3 - - iodate
HIO 4 - metaiodine	IO 4 - - metaperiodate
H 5 IO 6 - orthoiodine	IO 6 5- - orthoperiodate
HMnO 4 - manganese	MnO4- - permanganate
	MnO 4 2- - manganate
	MoO 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
	HPO 4 2- - hydroorthophosphate
	H 2 PO 4 - - dihydroothophosphate
H 4 P 2 O 7 - diphosphoric	P2O74- - diphosphate
	ReO 4 - - perrhenate
	SO 3 2- - sulfite
	HSO 3 - - hydrosulfite
H 2 SO 4 - sulfuric	SO 4 2- - sulfate
	HSO 4 - - hydrogen sulfate
H 2 S 2 O 7 - disulfur	S 2 O 7 2- - disulfate
H 2 S 2 O 6 (O 2) - peroxodisulfur	S 2 O 6 (O 2) 2- - peroxodisulfate
H 2 SO 3 S - thiosulfur	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 - metatelluric	TeO 4 2- - metatellurate
H 6 TeO 6 - orthotelluric	TeO 6 6- - orthotellurate
	VO 3 - - metavanadate
	VO 4 3- - orthovanadate
	WO 4 3- - tungstate

Less common acid hydroxides are named according to nomenclature rules for complex compounds, e.g.

Basic and acidic oxides. Chemical properties of basic oxides. Basic oxides react