The local structure of glasses of composition As-2(1-x)Sb2xS3 with x =
0-0.8 is studied by different techniques: Sb-121 Mossbauer spectrosco
py, infrared and optical absorption experiments. The results are consi
stent with a model of the glasses formed by a random distribution of A
sS3 and SbS3 trigonal pyramidal units connected by sulphur atoms. The
variations in the experimental data with Sb2S3 concentration can be co
rrelated with the substitution of Sb atoms for As atoms.