The chemical formula for nickel (II) permanganate is Ni(MnO₄)₂. Here's how we get that:

* Nickel (II): This tells us the nickel ion has a +2 charge (Ni²⁺).

* Permanganate: This is the polyatomic ion MnO₄⁻, with a -1 charge.

To balance the charges, we need two permanganate ions for every nickel ion:

* Ni²⁺ + 2(MnO₄⁻) → Ni(MnO₄)₂