A low-temperature phase of bis(tetrabutylammonium) octa-μ₃-chlorido-hexachlorido-octahedro-hexatungstate

Abstract

The title compound, (C₁₆H₃₆N)₂[W₆Cl₁₄], undergoes a reversible phase transition at 268(1) K. The structure at 150 and 200 K has monoclinic (P2₁/c) symmetry. Both crystallographically independent tungsten chloride cluster anions sit on crystallographic inversion centers [symmetry codes: (x, y+1, z) and (x+1, y+2, z)]. Two previous studies at room temperature describe the structure in the space group P2₁/n with a unit-cell volume approximately half the size of the low-temperature unit cell [Zietlow, Schaefer et al. (1986). Inorg. Chem. 25, 2195–2198; Venkataraman et al. (1999). Inorg. Chem. 38, 828–830]. The unit cells of the room- and low- temperature polymorphs are closely related. The hydrocarbon chain of one of the tetrabutylammonium cations is disordered at both 150 and 200 K.