CHEMICAL NAMES AND FORMULAS FOR IONIC COMPOUNDS
Chemical nomenclature is the system and rules used for naming chemical compounds.
These rules are set up by an international organization of scientists called the International
Union of Pure and Applied Chemistry (IUPAC).
Synonyms: 1,3,7-trimethyl-2,6-dioxo-1,2,3,6-tetrahydropurine; Alert-Pep;
Caffeine; Cafipel; eldiatric c; Guaranine; Koffein; Mateina; No-Doz; organex;
Refresh'n; Stim; Theine;
Why the heck do we need a naming system?
Comparison Chart for
Determing Charges of
Elements from the Periodic
Table
Groups
1
2
13
14
15
16
17
18
-
1
2
3
4
5
6
7
8
1+
2+
3+
4+/-
3-
2-
1-
0
Val. e
Charge
BINARY IONIC COMPOUNDS
Chemical Formula  Chemical Name
RULES:
Examples:
KCl
NaI
BeO
Ca3N2
Li2S
Chemical Name Chemical Formula
RULES
Examples:
Strontium sulfide
Barium fluoride
Sodium Nitride
Potassium oxide
Lithium Hydride
BINARY IONIC COMPOUNDS WITH MULTIVALENT ELEMENTS
 Transition metals can have more than one charge. The elements with more than one
charge are shown on your periodic table.
 For example, copper has +1 and +2. Copper (I) and copper (II) when bonded to another
anion, can have different physical properties.
 If bonded with chlorine, this could result in
CuCl CuCl2 –

Element
Copper
Iron
Lead
Mercury

The IUPAC system uses roman numerals in brackets to distinguish valences
Ion
Cu+
Cu2+
Fe2+
Fe3+
Pb2+
Pb4+
Hg22+
Hg2+
IUPAC System
copper (I)
copper (II)
iron (II)
iron (III)
lead (II)
lead (IV)
mercury (I)
mercury (II)
Classical
cuprous
cupric
ferrous
ferric
plumbous
plumbic
mercurous
mercuric
Element
nickel
Gold
cobalt
tin
Ion
Ni2+
Ni3+
Au1+
Au3+
Co2+
Co3+
Sn2+
Sn4+
IUPAC System
nickel (II)
nickel (III)
gold (I)
gold (III)
cobalt (II)
cobalt (III)
tin (II)
tin (IV)
Classical
nickelous
Nickelic
aurous
auric
cobaltous
Cobaltic
stannous
stannic
When determining the formula, criss-cross the charges as before, except this time use the
charge that matches with the roman numeral
Examples:
manganese (II) chloride
tin (IV) fluoride
iron (III) phosphide
cobalt (II) nitride
lead (II) oxide
FeCl2
FeCl3
CuS
SnS2
Pb(SO4)2
IONIC COMPOUNDS WITH POLYATOMIC IONS
 Compounds that contain polyatomic ions are also called polyatomic ionic compounds
because they have three or more elements and still contain a cation and anion.
 Polyatomic ions are ions that have more than one type of atom, usually oxygen included.
 The most important ones are included in your textbook and your study sheet
 When determining the formula, use the charges of the ions and criss-cross.
 Note: Most polyatomic ions have a negative charge. Ammonium has a positive charge.
Common Anions Acronym:
Examples:
NH4ClO3
Al2(SO4)3
Pb(NO3)4
Cu(OH)2
iron (III) hydroxide
calcium carbonate
magnesium phosphate
copper (I) cyanide
POLYATOMIC IONS WITH OXYGEN
 Some polyatomic ions have a differing number of oxygen atoms. When you add or remove
oxygens, the charges do not change, but the name does. The base ion is the one with the
‘ate’ ending.
Format:
Examples:
Na2CO2
Al2(SO5)3
Mg(NO2)2
Parent Polyatomic Ion
‘- ate’
Example: chlorate ClO3-
Add one oxygen
‘per – ate’
Example:
Remove one oxygen
‘- ite’
Example:
Remove two oxygens
‘hypo – ite’
Example:
lithium hypophosphite
potassium chlorite
beryllium pernitrate