Question

What is the IUPAC name for the compound “FeS”?

Answer 1

Hint: To name the compound “FeS'', we need to recognise that the compound has a metal, that is Fe and a nonmetal, that is S. So, we will name this as an ionic compound. Also, remember to check the periodic table for the charges on each ion.

Complete answer:
-The given compound “FeS” contains metal and a non-metal and so, we will name this as an ionic compound. Specifically, because they are two different elements of a binary ionic compound.
-The first step in this procedure is to name the metal as it appears on the periodic table, as it will form a positively charged ion or a cation. And in the next step, we will name the negatively charged ion or the anion. So we have Iron and sulphur, we replace the ending of sulphur with “ide”.
-So, at this point, we have Iron sulphide. However, Iron is a transition metal and so, it can have different charge depending on what it is bonded to and here it is bonded to sulphur which has a $2-$ ionic charge. So iron has to be $2+$ and to represent this on the naming system, we need to use the roman number. Therefore, the IUPAC name for the compound “FeS” is Iron $(II)$ sulphide.

Note:
There is a possibility that you might see the name starting with Ferrous in some places but that is an old name. So the official and the latest name of FeS is clearly formulated in the above-mentioned solution.