When aqueous solutions of chromium(II) iodide and sodium phosphate are combined, solid chromium(II) phosphate and a solution of sodium iodide are formed. The net ionic equation for this reaction is:

3 Cr²⁺(aq) + 2 PO₄³⁻(aq) ⇄ Cr₃(PO₄)₂(s)

Explanation:

When aqueous solutions of chromium(II) iodide and sodium phosphate are combined, solid chromium(II) phosphate and a solution of sodium iodide are formed. The molecular equation is:

3 CrI₂(aq) + 2 Na₃PO₄(aq) ⇄ Cr₃(PO₄)₂(s) + 6 NaI(aq)

The full ionic equation includes all the ions and the molecular species.

3 Cr²⁺(aq) + 6 I⁻(aq) + 6 Na⁺(aq) + 2 PO₄³⁻(aq) ⇄ Cr₃(PO₄)₂(s) + 6 Na⁺(aq) +         6 I⁻(aq)

The net ionic equation includes only the ions that participate in the reaction and the molecular species.

3 Cr²⁺(aq) + 2 PO₄³⁻(aq) ⇄ Cr₃(PO₄)₂(s)