Ionic Compounds Using the Common Naming System

Ionic Compounds Using the Common Naming System tutorial

When elements have more than one charge, it is important to distinguish which charge is being used. We will do this in the way we name the ion. This tutorial explains how to use the common naming system.

The chart below lists the common names of the metal ions that use the common naming system. This chart is also available as a pop-up from the tools menu by clicking common names.

Common Names of Metal Ions
Formula	Common Name
Au1+	aurous
Au3+	auric
Co2+	cobaltous
Co3+	cobaltic
Cu1+	cuprous
Cu2+	cupric
Fe2+	ferrous
Fe3+	ferric
(Hg2)2+	mercurous
Hg2+	mercuric
Ni2+	nickelous
Ni3+	nickelic
Pb2+	plumbous
Pb4+	plumbic
Sn2+	stannous
Sn4+	stannic

Two typical names of chemicals up to this point in history are "foliated earth of tartar" and "phlogisticated vitriolic acid.” There were hundreds of such names. One goal of the Méthode was to create chemical names based on the chemical composition.

Lavoisier's solution was to use different suffixes to indicate differences in composition. Specifically, the use of "-ous" and "-ic" will be studied.

The IUPAC (International Union of Pure and Applied Chemistry) says "The following systems are in use but not recommended: The system of indicating valence by means of the suffixes -ous and -ic added to the root of the name of the cation may be retained for elements exhibiting not more than two valences."

Antoine Lavoisier
"Father of Modern Chemistry"

How to Write a Formula for an Ionic Compound using the Common Naming System

Let’s try this one. Write the formula for ferric oxide.

Description of Action	Action
1. Use your chart to find the symbol and charge for the given common name. Write the symbol and charge for this ion.	1. Fe3+
2. To the right of the cation, write the anion and its charge.	2. Fe3+ O2-
3. Cross each element’s oxidation number to the lower right side of the other element’s symbol.	3. Fe3+ O2- Result: Fe2- O3+
4. Remove all (+) signs, (-) signs and ones.	4. Fe2O3
5. Reduce if necessary. Remember, if you are using a polyatomic ion, DO NOT touch anything in the parenthesis.	5. Not Necessary: Fe2O3
6. If you are using a polyatomic ion and there is no number outside of the parenthesis, you can remove the parenthesis.	6. No polyatomic ions: Fe2O3