Conductivity of a new pyrophosphate Sn0.9Sc0.1(P2O7)1-δ prepared by an aqueous solution method

New pyrophosphate Sn0.9Sc0.1(P2O7)(1-delta) was prepared by an aqueous solution method. The structure and conductivity of Sn0.9Sc0.1(P2O7)(1-delta) have been investigated. XRD analysis indicates that Sn0.9Sc0.1(P2O7)(1-delta) exhibits a 3 x 3 x 3 superstructure. It was found that Sn0.9Sc0.1(P2O7)(1-delta) prepared by an aqueous method is not conductive. The total conductivity of Sn0.9Sc0.1(P2O7)(1-delta) in open air is 2.35 x 10(-6) and 2.82 x 10(-9) S/cm at 900 and 400 degrees C respectively. In wet air, the total conductivity is about two orders of magnitude higher (8.1 X 10(-7) S/cm at 400 degrees C) than in open air indicating some proton conduction. SnP2O7 and Sn0.92In0.08(P2O7)(1-delta) prepared by an acidic method were reported fairly conductive but prepared by similar solution methods are not conductive. Therefore, the conductivity of SnP2O7-based materials might be related to the synthetic history. The possible conduction mechanism of SnP2O7-based materials has been discussed in detail. (C) 2009 Elsevier B.V. All rights reserved.