European journal of solid state and inorganic chemistry vol:30 issue:1-2 pages:165-177
Density measurements, powder X-ray diffraction diagrams, Te-125 Mossbauer isomer shifts and quadrupole splittings, optical studies are reported for S1-xTex (0 < x < 1). The different results provide evidence for the formation of S7Te rings (0 < x less-than-or-equal-to 0.05), then by opening of these rings (0.05 < x < 0.33) the formation of copolymer chains (limit composition TeS2). In the tellurium solid solution range (0.85 < x < 1) sulphur atoms are included in [Te]n chains (limit composition Te17S3). Optical studies indicate existence of large gaps (2.8-3.4 eV) for x less-than-or-equal-to 0.33 in agreement with the covalency of the Te - S bonds (2.47-2.86 angstrom). Beyond this composition (x=0.33) one can observe non-existent gaps like for elemental tellurium.