* Chromium (III) indicates that chromium has a +3 charge (Cr³⁺).
* Sulfide refers to the sulfur ion, which has a -2 charge (S²⁻).
To balance the charges, you need two chromium ions (2 x +3 = +6) and three sulfide ions (3 x -2 = -6). This gives you the formula Cr₂S₃.
