CLASSIFICATION OF COMPOUNDS

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* Binary compounds

* Ternary Compounds

Lavoisier proposed that the name of a compound must describe its composition, and this rule is applied in chemical nomenclature systems.

For purposes of the variety name of inorganic chemical compounds, it is necessary grouped into categories of compounds. One classifies them according to the number of elements that make up the compound, thus distinguishing. (1) the binary copmpuesto and (2) the ternary compounds.

BINARY COMPOUNDS

Binary compounds consist of two different elements. Being able to attend their composition these are classified as:

* Oxygen compounds or oxides.

The oxides are formed of oxygen and other elements. If the element is a metal, metal oxides are called, nonmetallic oxides and if the other element is a nonmetal.

* Metal oxides or basic oxides. (M + O2)

* Traditionally, when the metal has more than one valence, to refer to these oxides, is added to the metal name ending in “bear” or “ico” as higher or lower valence.

Another way is to designate these oxides valence state by a Roman numeral: these are the names of Stock (German chemist of the century).

EXAMPLES:

Traditional Formula Name Name Stock

Sodium oxide Na2O tin oxide

Stannous oxide SnO tin oxide (II)

Stannic oxide SnO2 tin oxide (IV)

Ferrous oxide FeO iron oxide (II)

Ferric oxide Fe2O3 iron oxide (III)

Cuprous oxide Cu2O copper oxide (I)

Cupric oxide CuO of copper oxide (II)

* Non-metallic oxides. (NM + O2)

To name these oxides applies the same rule that applies to the metal oxides. An important group of non-metal oxides can react with water to give rise to compounds known as oxyacids, and these oxides are called “anhydrides”. In the traditional nomenclature differ valences non-metal through the suffixes “bear” and “ico” and the prefix “hypo” and “per” according to the following scheme:

valence

growing

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EXAMPLES:

Traditional Nomenclature Nomenclature Formula Stock

Silicic anhydride SiO2 silicon oxide

Phosphorus oxide P2O3 phosphorous anhydride (III)

P2O5 phosphoric anhydride, phosphorus oxide (V)

Cl2O oxide chlorine hypochlorous anhydride (I)

Chlorous anhydride Cl2O3 chlorine oxide (III)

Cl2O5 chlorine dioxide from chloric oxide (V)

Perchloric oxide Cl2O7 chlorine dioxide (VII)

* BINARY COMPOUNDS HYDROGENATED.

In this group there are two subgroups:

* Hydrides. compounds formed by hydrogen and a metal. Are named with the word

generic “hydride” followed by the name of the metal.

EXAMPLE:

Formula Name

LiH lithium hydride

Sodium hydride NaH

Aluminum hydride AlH3

* The hydrido or hydrazides. compounds consisting of hydrogen and a non-metal.

EXAMPLE:

Formula Name

Hydrogen chloride HCl

hydrochloric acid

Hydrogen bromide HBr

hydrobromic acid

Hydrogen sulfide H2S

sulhdrico acid

Hydrogen nitride NH3

ammonia

Hydrogen phosphide PH3

phosphine

* Binary salts.

These salts are binary compounds containing a metal and non-metal. They are called using the name of the non-metal end in the suffix “ide” and then placing the name of the metal by a Roman numeral indicates the oxidation state of the metal when it has more than one valence.

EXAMPLE:

Traditional Nomenclature Nomenclature Formula Stock

KBr potassium bromide potassium bromide

Ferrous chloride FeCl2 iron chloride (II)

FeCl3 ferric chloride ferric chloride (III)

Cupric sulfide CuS sulfide copper (II)

Ternary compounds

They are called ternary compounds to those which are formed by three different elements. This group of compounds, like the binary includes subtancias belonging to different functions. The most important are:

* Hydroxides.

* Oxygenated acids or oxyacids.

* Salts derived from oxygenated acids.

* Formulation and NOMENCLATUAR hydroxides.

From the point of view of its chemical formula, the hydroxides may be considered consisting of a monovalent group metal and the OH (hydroxyl radical). Therefore, the formulation of hydroxides follows the same pattern as that of binary compounds.

EXAMPLE: Write the formula of aluminum hydroxide.

* The symbol is written to the OH group Al and enclosed in parentheses: Al (OH)

* Valences are exchanged: Al1 (OH) 3

* Deleted subscript 1: Al (OH) 3

The hydroxides of the general formula is: M (OH) n, where “n” indicates the number of OH groups bonded to metal.

To name hydroxides used the word “hydroxide” followed by the name of the metal, Roman numeral indicating the valence of the metal, as is the case.

EXAMPLE:

Traditional Nomenclature Nomenclature Formula Stock

Potassium hydroxide, KOH Potassium hydroxide

Al (OH) 3hidrxido aluminum hydroxide, aluminum

Fe (OH) 2 hydroxide ferrous hydroxide iron (II)

Fe (OH) 3 hydroxide ferric hydroxide iron (III)

* FORMULATION AND NOMENCLATURE U oxyacids oxygen acids.

Oxyacids is composed of H, a non-metal and O. To write oxyacids formulas, the symbols of the atoms are noted in the following order:

1st symbol of the hydrogen atoms.

2 The central command, which gives its name to oxyacid.

3 the symbol of oxygen.

Each with their respective subscript:

HnXOm

Most oxyacids may be obtained by the reaction of an anhydride with water. Therefore, to name oxyacids changes the word “anhydride” by “acid.”

EXAMPLE:

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Some special situations.

* To see the graph select the “Download” top menu

Here there is the special case that two molecules combine chromic anhydride with water:

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* Let us first chrome anhydrides and acids must originate:

* The anhydrides of P, As and Sb can be combined with one, two or three water molecules, for differentiating oxyacids which will originate, META prefixes are used, pyro and ortho, for one, two or three water molcukas respectively.

i) A water molecule.

metafosforoso acid

metaantimnico acid

ii) Two water molecules.

piroarsnico acid

piroantimonioso acid

iii) three water molecules.

Orthophosphoric acid

ortoarsenioso acid

*

* FORMULATION AND CLASSIFICATION OF SALES.

The procedure for establishing the formula of a ternary salt, is analogous to that used for binary salts, the fundamental difference is that in this case by replacing the hydrogen, there are two elements to combine with the metal.

A simple way to determine the salt formula is:

EXAMPLE:

1)

*

To name ternary salts, simply changing the suffix of the acid that originates in the following way:

Traditional system System Formula Stock

Fe2 (SO4) 3 iron sulfate, ferric sulfate (III)

Sodium nitrate NaNO 3 Sodium nitrate

Al (ClO4) aluminum perchlorate, aluminum perchlorate

Plumboso selenite selenite PbSeO3 lead (II)

Cu (NO2) 2 nitrite nitrite cupric copper (II)

Co3 (PO4) 2 cobaltous orthophosphate orthophosphate cobalt (II)

Ni (IO) 3 hypoiodite niqulico hypoiodite nickel (III)

Ca (ASO3) 2 calcium metaarseniato calcium metaarseniato

Mercuric chromate chromate HgCrO4 mercury (I)

K2Cr2O7 potassium dichromate, potassium dichromate

 

 

 

 

PATRICK E. CARREO