Is Potassium Phosphide Ionic or Covalent

Ionic bond: Potassium Phosphide (K3P)

Is phosphate ionic or covalent?

phosphate is an ion but all the bonds internally are covalent bonds.

Is potassium and sulfur ionic or covalent?

The difference in charge between the two 1+ potassium ions and the 2- sulfur ion allows electrostatic attraction between the sulfur ions and potassium ions. This is an ionic bond and is the basis of the ionic compound formed, as the differently charged ions are held together by their opposite charges.