EXAFS STUDY OF THE STRUCTURE OF AMORPHOUS AND CRYSTALLINE ARSENIC OXIDE

An analysis of the EXAFS spectra of crystalline and amorphous forms of arsenic oxide, Ass03, has been made. A fit of the single-scattering component of the spectrum gives details of the atomic environment surrounding an arsenic atom out to a distance of 4 A from it. The results for the known structure of the crystal, arsenolite, are used as a check on our calculated scattering properties. Interatomic distances and their mean square variation are presented for both forms. These show that the As-O bond length and As-O-As bond angle are the same in the crystal and the glass. The results for the glass show that its structure is more akin to claudetite than arsenolite, and that As4O6 molecular units are unlikely to exist as well defined entities in the glass. © 1979 Taylor and Francis Ltd.