REEXAMINATION OF THE CRYSTAL-STRUCTURE OF ZRTE3

Re-examination of the crystal structure of ZrTe3 by single-crystal methods shows that ZrTe3, contrary to earlier reports, takes the type A structure for MX3 compounds. Repeated syntheses of a large number of crystals, using various conditions in the transport reactions, gave only type A crystals. The powder X-ray and neutron diffraction patterns are only compatible with a type A bulk material. Two other representatives of the type B class of MX3 compounds were studied, but in less detail. However, the present results clearly show that their structures are also of type A. No indication for a type B material was found for any of these compounds. It is recommended that property measurements of low-dimensional MX3 compounds are accompanied by structural characterization in order to ascertain the type of the studied material. A list of Bragg reflections (powder X-ray diffraction data), particularly suited for differentiating between type A and type B materials, is provided.