Question

What is the formula for copper (l) sulfide?

Answer 1

`"Copper(I) sulfide"-="cuprous sulfide"-=Cu_2S`

Explanation:

Copper metal can access two common oxidation states, i.e. `Cu^+` or `Cu^(2+)`:

`underbrace(Cu_2S)_"copper(I) sulfide or cuprous sulfide"`;

`underbrace(CuS)_"copper(II) sulfide or cupric sulfide"`.

As are most sulfide salts, both salts would be as soluble as bricks in aqueous solution, and are poorly characterizable...