Die Antimonid–Triantimonidometallate(III) Cs6K3Sb[AlSb3] und Cs6K3Sb[GaSb3]

The Antimonide Triantimonidometallates(III) Cs₆K₃SbAlSb₃] and Cs₆K₃SbGaSb₃] The novel compounds Cs₆K₃SbAlSb₃] and Cs₆K₃SbGaSb₃] are formed from stoichiometric mixtures of Cs, AlSb (GaSb) and KSb in sealed niobium ampoules at 950 K. The hexagonal structures are especially characterized by one-dimensional rod packings ¹∞Cs₆K₃Sb] which are formed from columns of condensed (Cs₆K_6/2) icosahedra. The icosahedra are centered by Sb^3-? anions. The trigonal planar anions AlSb₃]^6-? and GaSb₃]^6-? are embedded between the icosahedra columns, and they are coordinated by alkali metal atoms. The FIR spectra were assigned to the vibrations of the MSb₃]^6-? anions, with respect to the 6 m2-D_3h symmetry. (P6₃/mmc, No. 194; a = 1101.7 and 1097.2 pm; c = 1158.9 and 1150.1 pm; Z = 2; Single crystal data: 574 and 546 reflections; R = 0.073 and 0.029. Distances:d(Al? Sb) = 265.4 pm; d(Ga? Sb) = 265.1 pm; d(Sb? Cs) = 401.6–423.0 pm; d(Sb? K) = 358.6–367.3 pm).