Final answer:
The formula for cobalt(II) phosphate is Co3(PO4)2, which is derived by balancing the charges of the cobalt(II) cations and phosphate anions to get a neutral compound.
Step-by-step explanation:
The formula for cobalt(II) phosphate is derived by combining the cobalt(II) cation (Co2+) with the phosphate anion (PO43-). Since cobalt(II) has a 2+ charge and phosphate has a 3- charge, we need to balance the charges to get a neutral compound. This is achieved by taking three cobalt ions for every two phosphate ions, giving us the formula Co3(PO4)2.