Short- and long-range ordering of vacancies in non-stoichiometric zirconium sulphide

Electron diffraction has been used to study the structure of Zr1−x S over a range of non-stoichiometric compositions. Two different superlattices of the NaCl type structure have been observed resulting from the long-range ordering of zirconium vacancies. At certain compositions a diffuse intensity distribution has been recorded in the diffraction patterns which has been attributed to short-range vacancy ordering. The measured superconducting transition temperatures are related to the degrees of ordering present.