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

New pyrophosphate Sn0.9Sc0.1(P2O7)1−δ was prepared by an aqueous solution method. The structure and conductivity of Sn0.9Sc0.1(P2O7)1−δ have been investigated. XRD analysis indicates that Sn0.9Sc0.1(P2O7)1−δ exhibits a 3 × 3 × 3 super structure. It was found that Sn0.9Sc0.1(P2O7)1−δ prepared by an aqueous method is not conductive. The total conductivity of Sn0.9Sc0.1(P2O7)1−δ in open air is 2.35 × 10−6 and 2.82 × 10−9 S/cm at 900 and 400 °C respectively. In wet air, the total conductivity is about two orders of magnitude higher (8.1 × 10−7 S/cm at 400 °C) than in open air indicating some proton conduction. SnP2O7 and Sn0.92In0.08(P2O7)1−δ 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.