The molecule PO4 3− has four oxygen atoms surrounding a central phosphorus atom, with a negative charge of 3. The electronegativity of oxygen is 3.44, while that of phosphorus is 2.19. This difference in electronegativity causes the electrons to be shared unequally, resulting in polar bonds between the phosphorus and oxygen atoms. The geometry of the molecule is tetrahedral, with the four oxygen atoms arranged at the corners of a tetrahedron. The phosphorus atom is located at the center of the tetrahedron. The polar bonds between the phosphorus and oxygen atoms create a net negative charge on the molecule, making it polar.