What is the chemical formula for ammonium phosphate?

Ammonium phosphate is an inorganic salt formed from ammonium ions and phosphate ions. The ammonium ion, NH4+, has a +1 charge, while the phosphate ion, PO4^3-, has a -3 charge. To determine the correct chemical formula, the charges must balance out.

In this case, since the phosphate ion carries a -3 charge, it requires three ammonium ions, each contributing a +1 charge, to achieve charge neutrality. This results in the combination of three NH4+ ions with one PO4^3- ion, leading to the chemical formula (NH4)3PO4.

In this formula, the three ammonium ions effectively neutralize the charge from the single phosphate ion, resulting in a stable compound. The other choices do not achieve the correct charge balance and thus do not represent ammonium phosphate.