Inorganic co-crystal formation and thermal disproportionation in a dicyanometallate ‘superperovskite’

Abstract

We report the synthesis, crystal structure, and thermally-driven phase transformation of the dicyanometallate superperovskite co-crystal [NBu₄]Mn[Au(CN)₂]₃·[NBu₄]ClO₄. This phase is understandable in terms of the conventional ABX₃ perovskite structure type, but with the NBu₄⁺ A-site cation displaced onto the perovskite cage face and 1-dimensional AX′ chains included within framework pores opened up by these displacements. On heating to 380 K, the co-crystal disproportionates into its two inorganic components: a bcs-structured ABX₃ phase and [NBu₄]ClO₄. This system illustrates a new type of structural and phase complexity accessible to dicyanometallate perovskites.