FeS is not a chemical equation, it's a chemical formula. It represents the compound iron sulfide.

There are no reactants or products in a chemical formula, so you can't write a chemical equation for it. However, you can write chemical equations that involve FeS as a reactant or product.

For example, here's the chemical equation for the formation of FeS:

Fe(s) + S(s) → FeS(s)

This equation represents the reaction of solid iron (Fe) with solid sulfur (S) to produce solid iron sulfide (FeS).