The naming of ionic compounds requires correct identification of the cation and anion species present. In certain cases, the charge of the ion is important for accurate naming.
Standard chemistry naming principles identify the cation first in the name and the anion second. In ionic compounds, the cation is typically a metal, and the first portion of the compound's name is simply that metal. If the cation can exist naturally in multiple charged states, the charge of the metal, also known as the valence, should be identified in the compound name with Roman numerals. For example, iron can exist in the positive two- or positive three-charged state. These would be named iron (II) and iron (III), respectively.
The final step in naming an ionic compound is to properly identify the anion that is present. Anions can be a single ion, such as bromide, or complex molecules that are made up of multiple atoms, such as sulfate. For these complex anions, additional naming parameters are in place. Elements that are able to form multiple oxyanions, such as nitrogen and sulfur, have either an -ite or an -ate ending, depending on the number of oxygen molecules present. An example of a properly named ionic compound is iron (II) sulfate for the ionic formula Fe(SO4).