Vibrational spectra of M II3Pb(P 2O 7) 2 (M II = Ni, Co)

Abstract

Raman and IR spectra of polycrystalline Ni 3Pb(P 2O 7) 2 and Co 3Pb(P 2O 7) 2 have been recorded and analyzed. The internal modes are assigned in terms of PO 3 and POP vibrations. The results point to a bent POP bridge configuration in Co 3Pb(P 2O 7) 2 as in Ni 3Pb(P 2O 7) 2. In the cobalt compound, the P 2O 4− 7 ions are distorted. Non-coincidence of the majority of the Raman and IR bands confirms a centrosymmetric structure for Ni 3Pb(P 2O 7) 2, and Co 3Pb(P 2O 7) 2. The POP bridge angle is slightly higher in the cobalt compound than in the nickel compound.