IUPAC Rules for Inorganic Nomenclature

IONIC COMPOUNDS

Positive Ions (cations)

Monatomic positive ions take the names of the metal from which they are derived:
Ion Name
Na+ sodium ion
Ca2+ calcium ion
Al3+ aluminum ion

When a metal forms more than one ion, it is necessary to distinguish between these ions. The accepted practice today is to indicate the charge of the ion by a roman numeral in parenthesis immediately following the name of the metal:
Ion Name
Fe2+ iron(II)
Fe3+ iron(III)
Cu+ copper(I)
Cu2+ copper(II)
Sn2+ tin(II)
Sn4+ tin(IV)

The only common inorganic polyatomic positive ions are:
Ion Name
NH4+ ammonium
Hg22+ mercury(I) or mercurous

Negative Ions (anions)

Monatomic negative ions are named by adding the suffix -ide to the stem of the name of the nonmetal from which they are derived:
Ion Name
H- hydride
F- fluoride
Cl- chloride
Br- bromide
I- iodide
O2- oxide
S2- sulfide
Se2- selenide
Te2- telluride
N3- nitride
P3- phosphide
C4- carbide

The nomenclature of polyatomic anions is more complex. The names of the most common are:
Ion Formula
borate BO33-
carbonate CO32-
hydrogen carbonate (bicarbonate) HCO3-
hypochlorite ClO-
chlorite ClO2-
chlorate ClO3-
perchlorate ClO4-
chromate CrO42-
dichromate Cr2O72-
cyanide CN-
phosphite PO33-
phosphate PO43-
hydrogen phosphate HPO42-
dihydrogen phosphate H2PO4-
hydrogen sulfite (bisulfite) HSO3-
hydrogen sulfate (bisulfate) HSO4-
sulfite SO32-
sulfate SO42-
sulfide S2-
hydrosulfide HS-
hydroxide OH-
nitrite NO2-
nitrate NO3-
oxalate C2O42-
permanganate MnO4-
silicate SiO44-

Ionic Compounds

For ionic compounds, the name of the positive ion (cation) is given first, followed by the name of the negative ion (anion):
Compound Name
CaCl2 calcium chloride
Fe(ClO4)3 iron(III) perchlorate
FeBr2 iron(II) bromide
NaHCO3 sodium hydrogen carbonate
(NH4)2SO4 ammonium sulfate

COVALENT COMPOUNDS

For covalent compounds involving metals, the above rules are still used when metals are involved:
AlCl3 aluminum chloride
SnCl4 tin(IV) chloride

For compounds made up of nonmetals, the first element named is the one with lower electronegativity, with the second having the higher electronegativity:
Compound Name
HCl hydrogen chloride
H2S hydrogen sulfide
NF3 nitrogen fluoride

If more than one binary compound is formed by a pair of nonmetals, the Greek prefixes di (two), tri (three), tetra (four), penta (five), hexa (six), etc. are used to designate the number of atoms present. The mono- prefix is rarely used.
Compound Name
N2O5 dinitrogen pentoxide*
N2O4 dinitrogen tetroxide
N2O3 dinitrogen trioxide
N2O2 dinitrogen dioxide
N2O dinitrogen oxide
NO2 nitrogen dioxide
NO nitrogen oxide

*when immediately followed by a vowel, the a is dropped.

Many of the most common binary nonmetal componds have common names which are use more frequently:

Compound Name
H2O water
H2O2 hydrogen peroxide
NH3 ammonia
N2H4 hydrazine
PH3 phosphine
AsH3 arsine
NO nitric oxide
N2O nitrous oxide

Practice Quiz.Try to name the following compounds.

Compound   Name   ?  
NaF
H2S
K2CO3
FeCl3
Mg(OH)2
NH4Br
PbI2
Al2O3
CaS
CaSO3
CaSO4
Ca3(PO4)2
Na3N
Li2O
K2S
(NH4)2S
Fe2O3
Mg3P2
NaNO3
SO3
KCl
BaSO4
ZnCl2
AgNO3
WO3
CoCl2
TiO
    Answers
Compound Name
NaF Sodium Fluoride
H2S Hydrogen Sulfide
K2CO3 Potassium Carbonate
FeCl3 Iron(III) Chloride
Mg(OH)2 Magnesium Hydroxide
NH4Br Ammonium Bromide
PbI Lead(II) Iodide
Al2O3 Aluminum Oxide
CaS Calcium Sulfide
CaSO3 Calcium Sulfite
CaSO4 Calcium Sulfate
Ca3(PO4)2 Calcium Phosphate
Na3N Sodium Nitride
Li2O Lithium Oxide
K2S Potassium Sulfide
(NH4)2S Ammonium Sulfide
Fe2O3 Iron(III) Oxide
Mg3P2 Magnesium Phosphide
NaNO3 Sodium Nitrate
SO3 Sulfur Trioxide
KCl Potassium Chloride
BaSO4 Barium Sulfate
ZnCl2 Zinc Chloride
AgNO3 Silver Nitrate
WO3 Tungsten (VI) Oxide
CoCl2 Cobalt (II) Chloride
TiO Titanium (II) Oxide