Abstract: | Crystal Structure of (NH4)3SnF7: A Double Salt According to (NH4)3SnF6]F and not (NH4)4SnF8 (NH4)3SnF7 is obtained as colourless single crystals from the reaction of NH4HF2 with tin powder at 300°C. The crystal structure (cubic, Pm3m, Z = 1, a = 602.5(1) pm at 293 K; a = 598.0(1) pm at 100 K) contains SnF6]2? octahedra and lonesome F? ions surrounded by NH4+ cations only; it may be considered as a derivative of the Cu3Au-type of structure according to Cu3Au]□ ?(NH4)3SnF6]F. The F? ions of the SnF6]2? octahedra with their Sn4+ centre in the origin of the unit cell at m3m are disordered in different ways at 293 and 100 K, respectively. |