The charge separation reactions of P 2 + 4 have been investigated using the PEPIPICO (photoelectron-photoion-photoion coincidence) technique at photon energies between 25 and 48 eV. All four possible ion pairs are formed. The relatively low appearance energy of the ion pair P + + P + 3 provides an estimate of 25.4 eV for the vertical double ionization energy of P 4 . Dissociations producing P + + P + 2 or 2P + are mainly sequential, proceeding via the intermediate ions P 2 + 3 or P 2 + 2 respectively.