Synthesis and crystal structure of CsCu3O2, containing a new type of oxocuprate(I) polyanion

CsCu3O2 was prepared via the azide route. Stoichiometric mixtures of the precursors (CsN3, Cu2O and CuO) were heated in a special regime up to 450 degreesC and annealed at this temperature for 50 h in silver crucibles. Single crystals have been grown by subsequent annealing of as prepared powders at 450 degreesC for 2000 h in silver crucibles, which were sealed in glass ampoules under dried Ar. According to the X-ray analysis of the crystal structure (P3ml, Z = 1, a = 5.250(1), c = 5.442(1) Angstrom, gamma = 120degrees) copper is linearly coordinated by oxygen atoms. The CuO2-dumb-bells are connected to an infinite two-dimensional (infinityCu3O2)-Cu-2-network. CsCu3O2 is isostructural with CsCu3S2, CsAu3S2, CsAu3Se2 and RbAu3Se2.