CHEMICAL NOMENCLATURE
Unit 4
NAMING TYPE I BINARY COMPOUNDS
 Binary
compound
 Made up of 2 elements consisting of a
cation and an anion to make a Binary
Ionic Compound
 Made of a metal and non-metal element
RULES FOR NAMING TYPE I IONIC
COMPOUNDS
1. The cation is always named first and the anion
second
 2. A simple cation (obtained from a single atom) takes
its name from the name of the element. For example:
Na+ is called sodium in the name of compounds
containing this ion
 3. A simple anion (obtained from a single atom) is
named by taking the first part of the element name
(the root) and adding –ide. Thus the Cl- ion is called
Chloride
 4. Write the name for the compound by combining the
names of the ions

TABLE 1: COMMON SIMPLE CATIONS AND
ANIONS
Cations
H+
Li+
Na+
K+
Cs+
Be+
Mg2+
Ca2+
Ba2+
Al3+
Ag+
Name
Hydrogen
Lithium
Sodium
Potassium
Cesium
Beryllium
Magnesium
Calcium
Barium
Aluminum
Silver
Anion
HFClBrIO2S2-
Name
Hydride
Fluoride
Chloride
Bromide
Iodide
Oxide
Sulfide
EXAMPLES
NaCl
KI
CaS
CsBr
MgO
Name
Sodium chloride
Potassium iodide
Calcium sulfide
Cesium bromide
Magnesium oxide
TYPE II – NAMING BINARY IONIC COMPOUNDS
THAT CONTAIN METALS THAT FORM MORE THAN
ONE TYPE OF CATIONS
This type of compound contains a metal that can
form more than one type of cation (Transition
metals)
 Differs from the Type I in that you place the
Roman Numeral in the name
 The Roman numeral tells the charge on the ion,
not the number of ions present in the compound

EXAMPLES
 CuCl
 Cu(I)
chloride
 HgO
 Mercury
(II) oxide
TYPE III – NAMING BINARY COMPOUNDS
THAT CONTAIN ONLY NONMETALS
1. The first element in the formula is named first,
and the full element name is used
 2. The element is named as though it were an
anion
 3. Prefixes are used to denote the numbers of
atoms present. These prefixes are given in the
following table
 4. The prefix mono- is never used for naming the
first element.
 For example: CO is called carbon monoxide,
not monocarbon monoxide

PREFIXES USED TO INDICATE NUMBERS IN
CHEMICAL NAMES
Prefix
Number Indicated
Mono-
1
Di-
2
Tri-
3
Tetra-
4
Penta-
5
Hexa-
6
Hepta-
7
Octa-
8
EXAMPLES
 NO

Nitrogen monoxide
 N2O5

Di nitrogen pentaoxide
 SF6

Sulfur hexafluoride
 SO2

Sulfur dioxide
 P4O6

Tetra phosphorus hexaoxide
REVIEW
 Type
I
 Ionic compounds with metals that always
form a cation with the same charge
 Type II
 Ionic compounds with metals (usually
transition metals) that form cations with
various charges
 Type III
 Compounds that contain only nonmetals