Acta Cryst. (1997). B53, 95-101 [ doi:10.1107/S010876819601155X ]
Abstract: A new type of twinning occurring in intergrowth tungsten bronzes (ITB) is described, revealed by high-resolution electron microscopy. Across the twin boundary the two structure elements of hexagonal tungsten bronze- and tetragonally distorted ReO3-types are interchanged and grow in strict geometrical relationship to each other. The structure is thus `inverted' and in the general case the two `twin' parts represent different members of the structure family. Some members remain invariant upon inversion, however. This defect is most often seen as ribbons in an ITB matrix in Mo-doped samples CsxMoyWl-yO3, which require a lower synthesis temperature than pure tungsten bronzes. They may be frozen-in stages of a slow ordering process. A similar type of twinning might be found in other intergrowth structures.
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