New pyrophosphate Sn0.9Sc0.1(P2O7)1-d was prepared by an aqueous solution method. The structure and conductivity of Sn0.9Sc0.1(P2O7)1-d have been investigated. XRD analysis indicates that Sn0.9Sc0.1(P2O7)1-d exhibits a 3 × 3 × 3 super structure. It was found that Sn0.9Sc0.1(P2O7)1-d prepared by an aqueous method is not conductive. The total conductivity of Sn0.9Sc0.1(P2O7)1-d 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-d 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. © 2009 Elsevier B.V. All rights reserved.
- Sn 0.9 Sc 0.1 (P 2 O 7 ) 1-δ