* Copper(I) indicates that copper has a +1 charge (Cu⁺).
* Arsenide is the anion of arsenic, which has a -3 charge (As³⁻).
To balance the charges, we need three copper ions (3 Cu⁺ = +3) for every one arsenide ion (1 As³⁻ = -3).
Therefore, the molecular formula for copper(I) arsenide is Cu₃As.
