Final answer:
The formula of the compound is Na3PO4, also known as sodium phosphate.
Step-by-step explanation:
The formula of a compound that contains Na+ and PO4^3- ions is Na3PO4. This compound is called sodium phosphate. It consists of three sodium ions (Na+) for every one phosphate group (PO4^3-). The PO4 groups are discrete units, each consisting of one phosphorus atom and four oxygen atoms, with an overall charge of 3-.