Mixtures of Ag2SO4 and Ag2S with a silver sulphate content varying fro
m 16.67-50.0 mol.% were heated in air. The diffraction pattern of a sa
mple obtained by the heating of a physical mixture comprising 33.33 mo
l.% of Ag2SO4 consists of diffraction lines that could not be attribut
ed to any of the other phases existing in the Ag-OS system. The lines
have been ascribed to a new phase of monoclinic system having the form
ula, Ag6S3O4, which has been ascertained by chemical analysis.