Section 2.8
Naming Inorganic Compounds
Chemical Nomenclature
Naming system of substances
 Latin:

◦ Nomen~ name

Calare~ to call
Two main categories:
◦ Organic and Inorganic
Inorganic Compound Rules
Ionic
Acids
Molecular
Ionic Compounds
Compounds
Anions
Cations
Ionic Compounds

1. Cations
◦ a) Same name as the metal they formed from:
 Na+ sodium ion
◦ b) Metals forming different cations: use
Roman numerals in parentheses:
 Fe2+ iron (II) ion
 Fe 3+ iron (III) ion
~ Older method: -ous or –ic ending
Fe2+ ferrous ion Fe3+ ferric ion
Ionic Compounds

c) Cations formed from nonmetal atoms
have names that end in –ium
NH4+ ammonium ion
H3O+ hydronium ion
Ionic Compounds

2. Anions
◦ a) Monoatomic anions are formed by
replacing ending of name of element with –ide
O2- oxide
N3- nitride
◦ b) Polyatomic anions contain oxygen
(oxyanions) end in –ate or –ite
NO3- nitrate
NO2- nitrite
Ionic Compounds
◦ b) Polyatomic anions contain oxygen (oxyanions)
end in –ate or –ite
◦ -ite has one fewer O atoms than an –ate
 NO3- nitrate
 NO2- nitrite
◦ Prefixes per- and –hypo are used when there are
more than four members
 ClO4 ClO3 ClO2 ClO-
perchlorate
chlorate
chlorite
hypochlorite
Ionic Compounds

c) Anions derived from adding H+ to an
oxyanion: begin with either hydrogen or
dihydrogen
 CO32 HCO3-
carbonate
hydrogen carbonate
 PO43 H2PO43-
phosphate
dihydrogen phosphate
Ionic Compounds

3. Compounds
◦ Names consist of the cation name followed by
the anion name
 CaCl2
 AlPO3
 CuSO4
calcium chloride
aluminum phosphite
copper (II) sulfate
Acids
-ides
-ates /-ites
Acids

1. With anions ending in –ide: change –ide
to –ic, add the prefix hydro-, and follow
with the word acid
Anion
Corresponding Acid
Cl- (chloride)
HCl (hydrochloric acid)
S2- (sulfide)
H2S (hydrosulfuric acid
Acids

2. With anions ending in –ate or –ite:
◦ Change –ate to –ic
◦ Change –ite to –ous
◦ Add the word acid
Anion
Corresponding Acid
ClO4- (perchlorate)
HClO4 (perchloric acid)
ClO3- (chlorate)
HClO3 (chloric acid)
ClO2- (chlorite)
HClO2 (chlorous acid)
ClO- (hypochlorite)
HClO (hypochorous acid)
Molecular Compounds (Binary)
1. Name the element farther to the left in
the periodic table first.
 2. If both in same group, the one with the
higher atomic number is named first.
 3. Name the second with an –ide ending
 4. Greek prefixes are used to indicate
number of atoms of each element
