Hydrogen insertion, ESR and Mössbauer studies of Cu0.5TaFeP3O12

A new copper Nasicon of composition Cu0.5TaFeP3O12 has been prepared and reduced under hydrogen flow at 500 and 675 °C, separately. The unreduced and reduced products are characterized by IR spectra and powder X-ray diffraction. The copper Nasicon and the products obtained by its reduction crystallize in the rhombohedral lattice with space group R3¯c. The ESR and Mössbauer spectral results suggest only partial reduction of both Cu2+ and Fe3+ to Cu+ and Fe2+, respectively, with simultaneous hydrogen insertion to balance the charge. A reaction in conformity with the obtained results is proposed.