Phosphate is a polyatomic ion with the formula PO₄³⁻. It is composed of one phosphorus atom and four oxygen atoms. The phosphorus atom is in the center of the ion and is bonded to each of the oxygen atoms by a single covalent bond. The oxygen atoms are arranged in a tetrahedral shape around the phosphorus atom.

The phosphate ion is polar because it has a net negative charge. This means that the center of negative charge is not located at the same point as the center of positive charge. The center of negative charge is located closer to the oxygen atoms, while the center of positive charge is located closer to the phosphorus atom. This results in a dipole moment, which is a measure of the polarity of a molecule.