How are metals named in an ionic compound?

1 Answer
Jun 8, 2014

Just the same as their element name, but for elements that have variable oxidation numbers, e.g. the transition metals, we add a number in Roman numerals after the name to show what it's oxidation state is.

For example, in magnesium chloride, magnesium has its normal name and as it can only have +2 oxidation number it needs nothing more. Same for sodium chloride, aluminium chloride etc.

Iron, however can form +2 or +3 compounds, so if we consider the chlorides, we need to name them iron(II) chloride or iron(III) chloride respectively so we can tell them apart.

Occasionally we come across old names such as stannous chloride or stannic chloride (tin chlorides) or ferrous and ferric chloride (iron chlorides), These are old nomenclature and should no longer be used by Chemists as we have adopted IUPAC naming rules for clarity and to avoid ambiguity.