Preparation and crystal structure of barium caesium undecaphosphide‐ammonia (1/11) BaCsP11 · 11 NH3

The new compound BaCsP11 · 11 NH3 was prepared in liquid ammonia, using Cs3P11 and a cation exchange resin loaded with Ba2+ cations as starting materials. BaCsP11 · 11 NH3 forms yellow crystals which decompose at 246 K under loss of the ammonia of crystallisation. The crystal structure was determined from single‐crystal X‐ray diffractometer data: P21/a, a = 1599.9(2) pm, b = 1793.9(3) pm, c = 1998.1(7) pm, β = 93.02(4)°, Z = 8, wR2 = 0.118 (R1 = 0.047) for 8969 structure factors and 631 variable parameters. The Cs+ cations are co‐ordinated by undecaphosphatrishomocubane anions P113− in such a way that one‐dimensionally infinite chains [CsP11]2− result which are separated by Ba(NH3)n2+ (n = 8 and 9). Only one BaP contact is observed.