Naming of Inorganic Compounds

Naming of Inorganic Compounds

Basic Principles of Naming Inorganic Compounds

The name of an inorganic compound typically reflects its composition and structure.

The name often consists of the cation (positive ion) followed by the anion (negative ion).

For compounds with multiple oxidation states, the oxidation state is specified using Roman numerals in parentheses.

Naming Rules Structure:

Cation first \rightarrow element name (plus Roman numeral in parenthesis if more than one possible charge).

Anion second \rightarrow -ide ending (if binary compound) OR ion name (if polyatomic).

Examples:

\text{SrCl}_2– strontium chloride

\text{CoCl}_2 – cobalt(II) chloride

\text{Pt}_3(\text{AsO}_2)_4 – platinum(II) arsenate

Naming Simple Ionic Compounds

Composed of metal cations and non-metal anions.

The metal name is used first, followed by the non-metal root with an "-ide" suffix.

Examples to name:

\text{NaCl}– Sodium chloride

\text{K}_2\text{O} – Potassium oxide

\text{CaF}_2 – Calcium fluoride

Naming Transition Metal Compounds

Transition metals can have multiple oxidation states.

The oxidation state is indicated in Roman numerals in parentheses after the metal name.

Classic vs. Stock System Example:\text{FeCl}3isferricchloride(\text{Fe}^{3+})oriron(III)chloride,while\ \text{FeCl}{2\ }\ is\ f\ errous\ chloride\ (\text{Fe}^{2+})\ oriron\ (II)chloride.

Table of Common Transition Metal Ions:

Charge

Metal Ions

1+

Copper\ (I)\ (\text{Cu}^+),\ Gold\ (I)\ (\text{Au}^+),\ Mercury\ (I)\ (\text{Hg}_2^{2+}),\ Silver\ (\text{Ag}^+)

2+

Cadmium(\text{Cd}^{2+}),Chromium(II)(\text{Cr}^{2+}),Cobalt(II)(\text{Co}^{2+}),Copper(II)(\text{Cu}^{2+}),Iron(II)(\text{Fe}^{2+}),Lead(II)(\text{Pb}^{2+}),Manganese(II)(\text{Mn}^{2+}),Mercury(II)(\text{Hg}^{2+}),Nickel(II)(\text{Ni}^{2+}),Platinum(II)(\text{Pt}^{2+}),Tin(II)(\text{Sn}^{2+}),Zinc(\text{Zn}^{2+})

3+

Chromium(III)(\text{Cr}^{3+}),Cobalt(III)(\text{Co}^{3+}),Gold(III)(\text{Au}^{3+}),Iron(III)(\text{Fe}^{3+})

4+

Lead(IV)(\text{Pb}^{4+}),Tin(IV)(\text{Sn}^{4+})

Examples to name:

\text{FeCl}_3-Iron(III)chloride

\text{FeCl}_2-Iron(II)chloride

\text{CuSO}_4-Copper(II)sulfate

\text{Cr}_2\text{O}_3-Chromium(III)oxide

Naming Covalent (Molecular) Compounds

Consist of two non-metals.

Use Greek prefixes to indicate the number of atoms present:

mono- (1), di- (2), tri- (3), tetra- (4), penta- (5), hexa- (6), hepta- (7), octa- (8), nona- (9), deca- (10).

Examples:

\text{CO}_2-Carbondioxide

\text{N}_2\text{O}-Dinitrogenmonoxide

\text{P}4\text{O}{10}-Tetraphosphorusdecoxide

\text{SO}_3-Sulfurtrioxide

Naming Acids

Acids begin with H}.

Two Elements / Binary Acids (Anions ending in -ide):

Prefix "Hydro-" + stem + "-ic acid"

Example: \text{HCl}(chloride)\ \rightarrow Hydrochloric acid

Oxyacids (Anions ending in -ate):

Stem + "-ic acid"

Example:\text{HNO}_3(nitrate)\rightarrow Nitric acid

Oxyacids (Anions ending in -ite):

Stem + "-ous acid"

Example: \text{HNO}_2(nitrite)\rightarrow Nitrous acid

Names of Common Ions and Their Acids:

Ion Formula

Ion Name

Acid Formula

Acid Name

\text{Br}^-

Bromide

\text{HBr}

Hydrobromic acid

\text{CN}^-

Cyanide

\text{HCN}

Hydrocyanic acid

\text{NO}_2^-

Nitrite

\text{HNO}_2

Nitrous acid

\text{NO}_3^-

Nitrate

\text{HNO}_3

Nitric acid

\text{PO}_4^{3-}

Phosphate

\text{H}_3\text{PO}_4

Phosphoric acid

\text{SO}_3^{2-}

Sulfite

\text{H}_2\text{SO}_3

Sulfurous acid

\text{SO}_4^{2-}

Sulfate

\text{H}_2\text{SO}_4

Sulfuric acid

\text{ClO}^-

Hypochlorite

\text{HClO}

Hypochlorous acid

\text{ClO}_2^-