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How is the reaction between iron and sulfur represented by a chemical equation?

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chemistry A ball-and-stick model of molecular structure, showing atoms bonded together.

The reaction between iron (Fe) and sulfur (S) is a synthesis reaction that forms iron sulfide (FeS). This process is represented by the following chemical equation:

Fe(s) + S(s) → FeS(s)

In this equation, the symbols (s) denote that the reactants and the product are in the solid state. The plus sign indicates that iron and sulfur are reacting together, while the arrow signifies that the reaction yields the product, iron sulfide.1

Because matter is neither created nor destroyed during chemical reactions, the equation must be balanced. This specific reaction shows that one atom of iron reacts with one atom of sulfur to produce one formula unit of iron sulfide, ensuring the same number of atoms of each element appears on both sides of the equation.2