Our research group have been investigating the structure-property relationship in solid oxide fuel cell materials, with the aim of developing new materials with improved properties. A key aspect of our research programme is the investigation of novel doping strategies for Solid Oxide Fuel Cell (SOFC) materials, and in this respect the possibility to exploit oxyanion doping strategies in such materials is currently being investigated. A particular focus has been the incorporation of silicate to highlight the potential of such a doping strategy, and develop a suitable electrode to be used with apatite-type silicate electrolytes. We have examined Si doping into SrMnO3 and CaMnO3 endmembers as well as mixed La/Sr, La/Ca manganates, with the results showing significant (up to 20%) Si incorporation. In this experiment we will investigate in detail the structural effect of such substitution.