Zeuner, Martin; Hofer, Alexander; Schnick, Wolfgang (2009): Cs10Ta29.27O78. In: Acta Crystallographica, Vol. E65, Nr. 2: I12




Single crystals of caesium tantalate(V), Cs10Ta29.27O78, were obtained as a serendipitous product in a welded tantalum ampoule by a blank reaction of CsBr and bismuth subnitrate [Bi5O(OH)9(NO3)4] with the container material. The crystal structure of the title compound is made up of a three-dimensional framework constituted by two types of layers, viz. (Ta6O15)n and (Ta3O9)n, parallel to (001), which are linked together by TaO6 octahedra (3m. symmetry) along [001]. This framework has cavities where three independent Cs+ ions (3m. and 6m2 symmetry, respectively) are located. The compound reveals a Ta deficiency at one trigonal prismatic coordinated site (6m2 symmetry). The composition of the title compound was verified by energy-dispersive X-ray analysis of single crystals.