Copper sulfide is found written as both CuS and Cu2S. Why are there two forms for writing this chemical formula? SELECT AN ANSWER

This is an example of a combination reaction: CuS is the halfway stage, before the second copped atom joins the molecule.

Copper is a transition metal with two possible ionic states (copper I, or 1+, and copper II, or 2+).

This is a synthesis reaction and so the formula will continue changing until all the atoms have conglomerated.

One of the versions is a mistake, the correct form should be Cu2S.