Naming Ionic Compounds

Nomenclature - Ionic Compounds
Dr. MJ Patterson

 

To use this set of rules, the compound must be ionic.  In other words, it must be a metal + a nonmetal.  Or, it must contain one or more of the polyatomic ions.

Naming Polyatomic Ions

The polyatomic ions have names that you need to memorize.  See the previous Additional Study activity from the course web page.

Naming Main Group Metal Cations

A main group cation is named as the element followed by the word ion.

Example 1:
Name the following cations.
a.    Na+
b.    Al3+
c.    Ba2+

Solution 1:
a.    Na+    sodium ion
b.   
Al3+    aluminum ion
c.
    Ba2+    barium ion

Naming Transition Metal Cations

Since the transition metals can have various charges, you must specify the charge of the ion in the name with a Roman numeral in parentheses.
 

Roman Numeral

I

II

III

IV

V

VI

VII

Arabic Numeral

1

2

3

4

5

6

7

Example 2:
Name the following transition metal cations.
a.    Mn2+
b.    Mn7+
c.
    Fe2+
d.
    Fe3+

Solution 2:
a.    Mn2+    manganese(II) ion
b.    Mn7+    manganese(VII) ion
c.    Fe2+    iron(II) ion
d.    Fe3+    iron(III) ion

Naming Main Group Anions

The main group anions are named by placing the -ide ending on the element name and adding the word ion.

Example 3:
Name the following anions.
a.    Cl- 
b.    O2-
c.
    N3-
d.
    F-

Solution 3:
a.    Cl   chloride ion
b.
    O2-    oxide ion
c.
    N3-    nitride ion
d.
    F-    fluoride ion

Naming Ionic Compounds

To name an entire ionic compound, name the cation followed by the anion.  Omit the word "ion."

Example 4:
Name the following ionic compounds.
a.    NaCl
b.    BaF2
c.
    FeCl2 (iron has a +2 charge)
d.    CaO
e.
    NH4NO3

Solution 4:
a.    NaCl    sodium chloride
b.
    BaF2    barium fluoride
c.
    FeCl2 (iron has a +2 charge)    iron(II) chloride
d.    CaO    calcium oxide
e.
    NH4NO3    ammonium nitrate