CHEMICAL NOMENCLATURE
1. Binary Ionic Compounds - Type I
2. Binary Ionic Compounds - Type II
3. Ionic Compounds & Polyatomic (Complex) Ions
4. Hydrated Ionic Compounds
5. Binary Covalent Compounds
Definitions
 An IONIC COMPOUND consists of a metal
cation bonded to a nonmetal anion.
Electrostatic attraction holds them together.
 A COVALENT COMPOUND consists of two
nonmetal atoms sharing valence electrons.
 A BINARY compound is one that is made of
just two elements.
Type I Binary Ionic Compounds
 The metal cations in these compounds have
only ONE possible charge.
Na+
Zn2+
sodium
zinc
Al3+
Ca2+
aluminum
calcium
The charges are memorized or predicted using a periodic table!
 The cations are bonded to nonmetal anions:
O 2oxide
N3nitride
Ffluoride
Br bromide
Notice that simple anions are always named with the suffix
“ide”
 In an ionic compound, the charges of the
cations and anions must always cancel out.
 Subscripts are used if more than one atom is
needed to cancel the charges:
sodium chloride:
Na+ and Cl-  NaCl
lithium oxide:
Li+ and O2-  Li2O
aluminum bromide: Al3+ and Br -  AlBr3
zinc nitride:
Zn2+ and N3-  Zn3N2
potassium iodide:
K+ and I-  KI
silver phosphide:
Ag+ and P3-  Ag3P
Examples: Type I Binary Ionic
Compounds
Write the formulas:
Write the names:
•potassium oxide
• K3N
• zinc chloride
• AgI
• silver sulfide
• ZnBr2
• aluminum nitride
• Al2O3
• gallium oxide
• Ba3P2
•calcium iodide
• LiH
Type II Binary Ionic Compounds
 These are ionic compounds where the metal cation can
form TWO different charges.
Fe2+ iron (II)
Fe3+ iron (III)
Ni2+
Ni3+
nickel (II)
nickel (III)
Co2+ cobalt (II)
Co3+ cobalt (III)
Cu+
copper (I)
Cu2+ copper (II)
Au+
gold (I)
Au3+ gold (III)
Sn2+
tin (II)
Sn4+ tin (IV)
An older system uses suffixes and Latin names, -ous for the lower
charge, -ic for the higher charge:
Ferrous & Ferric, Cuprous & Cupric, Stannous & Stannic
Examples: Type II Binary Ionic
Compounds
Write the formulas:
Write the names:
• iron (II) oxide
• Fe2O3
• copper (II) chloride
• SnS
• tin (IV) sulfide
• NiBr2
• cupric nitride
•CuS
• nickel (III) oxide
• Pb3P2
• ferrous iodide
• CuBr
•cobalt (III) selenide
• FeCl3
Polyatomic (Complex) Ions
 All of the cations and anions so far have been simple ions -
single atoms that have lost or gained electrons.
 A molecule is a particle that forms when two or more
atoms bond together.
 A complex ion is a charged molecule. Complex ions may
be cations or anions.
examples:
nitrate: NO3-
sulfate: SO42- hydroxide: OH-
Common Polyatomic Ion Compound
Naming Examples…
a) Ammonium chloride
NH4Cl
b) Silver sulfate
Ag2SO4
c) Aluminum hydroxide
Al(OH)3
d) Calcium phosphate
Ca3(PO4)2
e) Iron (III) nitrite
Fe(NO2)3
f) Copper(II) permanganate
Cu(MnO4)2
g) Ammonium dichromate
(NH4)2Cr2O7
h) Zinc acetate
Zn(CH3COO)2
Things to Notice
 Most complex ions are anions. Ammonium, NH4+, is the
most common complex cation.
 Several complex ions form a short series of ions. The ions
differ only in the number of oxygen atoms:
perchorate
ClO4-
sulfate
SO42-
chlorate
ClO3-
sulfite
SO32-
chlorite
ClO2-
hypochlorite
ClO-
nitrate
NO3-
nitrite
NO2-
 If an ion carries a charge like “-2” or “-3”, a series of related ions
can be formed by adding hydrogen cations (H+) while still
leaving a net charge:
examples:
Sulfide:
S2-
hydrogen sulfide: HS(bisulfide)
Sulfate:
SO42-
hydrogen sulfate: HSO4(bisulfate)
Carbonate:
CO32-
hydrogen carbonate:
HCO3-
(bicarbonate)
Phosphate:
PO43-
hydrogen phosphate:
HPO42-
dihydrogen phosphate:
H2PO4-
More Formulas with Complex Ions
a) Sodium bicarbonate
NaHCO3
b) Nickel (II) hydrogen sulfide
Ni(HS)2
c) Aluminum perchlorate
Al(ClO4)3
d) Barium dihydrogen phosphate
Ba(H2PO4)2
e) Iron (III) sulfite
f) Cuprous bisulfate
Fe2(SO2)3
CuHSO4
g) Zinc periodate
h) Lithium selenite
Zn(IO4)2
Li2SeO3
Hydrated Ionic Compounds
 A HYDRATE is an salt that has water molecules trapped
within its crystals.
 Every hydrate has a certain number of water molecules
associated with each formula unit of the ionic compound.
The number of water molecules is indicated by using
prefixes.
1 mono
2 di
3 tri
4 tetra
5 penta
6 hexa
7 hepta
8 octa
9 nona
10 deca
CuSO4 · 5 H2O
copper (II) sulfate pentahydrate
MgCO3 ·10 H2O
magnesium carbonate decahydrate
Examples of hydrates:
 Write the formulas:
copper(II) fluoride tetrahydrate
CuF2 ·4 H2O
calcium nitrate trihydrate
Ca(NO3)2 ·3 H2O
 Write the names:
MgSO4 · 7 H2O
magnesium sulfate heptahydrate
FeCl2 · H2O
iron (II) chloride monohydrate
Binary Covalent Compounds
 Covalent compounds are made of two NONMETAL
elements sharing valence electrons.
 There are no ions involved!!
 Because there are no charges to help us write the formulas
of covalent compounds, prefixes are used to indicate the
number of each atom present in the formula.
CO2
CO
N2O
SO3
is named “carbon dioxide”
is named “carbon monoxide”
is named “dinitrogen monoxide”
is named “sulfur trioxide”
The prefix, “mono”
is never used for
the first element
in the formula!
Examples of Covalent Naming
 Write the names:
SO2
sulfur dioxide
P4O10
tetraphosphorus decoxide
 Write the formulas:
phosphorus pentachloride
PCl5
dinitrogen trioxide
N2O3