* Nickel (III): This tells us the nickel ion has a +3 charge (Ni³⁺).
* Sulfate: This is the polyatomic ion SO₄²⁻.
To balance the charges, we need two nickel (III) ions (2 x +3 = +6) and three sulfate ions (3 x -2 = -6):
* Ni₂(SO₄)₃
Therefore, the chemical formula for nickel (III) sulfate is Ni₂(SO₄)₃.
