High-resolution electron microscopy of crystallographic shear structures in tungsten oxides

Crystallographic shear (CS) structure in reduced crystals of W0₃ has been imaged at a resolution of 3–4A?by a high-resolution electron microscope.A?large distortion of the W0₆ octahedra sharing their edges at the CS planes has been directly recognized in electron micrographs.Crystallographic shear occurs preferentially in a particular crystallographic orientation. The preference may be explained by a different degree of distortion along the principal axes in the W0₆ octahedra of the pseudocubic structure of W03 crystal.A model for growth and ordering of the CS planes is discussed.