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)