Inorganic nomenclature

Inorganic nomenclature is a systematic way of naming inorganic compounds.
Positively charged ions are called cations and negatively charged ions are called anions. The cation is always named first. Ions can be metals or polyatomic ions. Therefore the name of the metal or positive polyatomic ion is followed by the name of the non-metal or negative polyatomic ion. The positive ion retains its element name whereas for a single non-metal anion the ending is changed to -ide.
Example: sodium chloride, potassium oxide, or calcium carbonate.
When the metal has more than one possible ionic charge or oxidation number the name becomes ambiguous. In these cases the oxidation number of the metal ion is represented by a Roman numeral in parentheses immediately following the metal ion name. For example in uranium(VI) fluoride the oxidation number of uranium is 6. However in this case the non IUPAC name uranium hexafluoride is often used. Another example is the iron oxides. FeO is iron(II) oxide and Fe₂O₃ is iron(III) oxide.
For naming metal complexes see the page on complex (chemistry).
Strictly nonmetal covalent compounds are named using Greek prefixes- for details see systematic name.
An older system used prefixes and suffixes to indicate the oxidation number, according to the following scheme:

Oxidation state	Cations and acids	Anions
Lowest	hypo- -ous	hypo- -ite
	-ous	-ite
	-ic	-ate
Highest	per- -ic	per- -ate

Thus the four oxyacids of chlorine are called hypochlorous acid (HOCl), chlorous acid (HOClO), chloric acid (HOClO₂) and perchloric acid (HOClO₃), and their respective conjugate bases are the hypochlorite, chlorite, chlorate and perchlorate ions. This system has partially fallen out of use, but survives in the common names of many chemical compounds: the modern literature contains few references to "ferric chloride" (instead calling it "iron(III) chloride"), but names like "potassium permanganate" (instead of "potassium manganate(VII)") and "sulfuric acid" abound.

List of common ion names

Polyatomic ions:

NH₄⁺ AMMONIUM

H₃O⁺ HYDRONIUM

NO₃^- NITRATE

NO₂^- NITRITE

ClO^- HYPOCHLORITE

ClO₂^- CHLORITE

ClO₃^- CHLORATE

ClO₄^- PERCHLORATE

SO₃^2- SULFITE

SO₄^2- SULFATE

HSO₃^- BISULFITE (or HYDROGEN SULFITE)

HCO₃^- BICARBONATE (or HYDROGEN CARBONATE)

CO₃^2- CARBONATE

PO₄^3- PHOSPHATE

HPO₄^2- HYDROGEN PHOSPHATE

H₂PO₄^- DIHYDROGEN PHOSPHATE

CrO₄^2- CHROMATE

Cr₂O₇^2- DICHROMATE

BO₃^3- ORTHOBORATE

AsO₄^3- ARSENATE

C₂O₄^2- OXALATE

CN^- CYANIDE

MnO₄^- PERMANGANATE

Monatomic anions:

Cl^- CHLORIDE

S^2- SULFIDE

P^3- PHOSPHIDE