Intergrowth tungsten bronzes

A series of phases has been found in the tungsten bronze systems M_xWO₃ for x ≤ 0.10 when M = K,Rb, Cs, Tl. The crystal structure of one of these was derived from a high-resolution electron micrograph (lattice image) and confirmed by X-ray diffraction analysis. It can be considered as an (ordered) intergrowth of slices of hexagonal tungsten bronze type with slabs of WO₃ structure type. Different members of the series characterized by different thicknesses of the WO₃ slabs have been observed. Members have been obtained only intermixed with others, never as single phases. Disorder in the form of varying widths of the two structure elements has been observed quite frequently.