Properties and structure of glasses in the system AsS

In obtaining the glass, at first, the raw materials were mixed up and melted by using porcelain crucible, but in this case it was found by infra-red absorption method that the glass contains some oxygen impurities. Then a range of glasses was prepared by melting elementary pure As and S in definite proportions in a sealed vacuum tube. The infra-red absorption, molecular volume, molecular refraction, hardness, thermal expansion and viscosity of sample glasses with various compositions were investigated and, additionally, solubility of these glasses into CS₂ was measured. The structure of glasses in the system AsS was studied by X-ray diffraction and a structural model was set up. From the measurements the following conclusions were made. The structure of As₂S₃ glass is a distorted form of the crystalline orpiment structure. With increasing S content above As₂S₃, S is likely to exist in the chain-like form, but when the S content is greater than that in As₂S_8–10, both chain-like and ring type forms co-exist. With decreasing S content below As₂S₃, S between As and As is eliminated and AsAs bonds are formed. Consequently a deformation of layer occurs and an expansion of the layer distance was observed.