Abstract
Single crystals of caesium tantalate(V), Cs(10)Ta(29.27)O(78), were obtained as a serendipitous product in a welded tantalum ampoule by a blank reaction of CsBr and bis-muth subnitrate [Bi(5)O(OH)(9)(NO(3))(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. (Ta(6)O(15))(n) and (Ta(3)O(9))(n), parallel to (001), which are linked together by TaO(6) octa-hedra (3m. symmetry) along [001]. This framework has cavities where three independent Cs(+) ions (3m. and m2 symmetry, respectively) are located. The compound reveals a Ta deficiency at one trigonal prismatic coordinated site (m2 symmetry). The composition of the title compound was verified by energy-dispersive X-ray analysis of single crystals.