Structure NaCl des phases AgxSn1−xX (X = S,Se)

A cubic phase was observed at room pressure in the case of Ag_xSn_1?xSe (.43 < x < .48). Under 65 Kbars and 1000°C, this cubic domain is enlarged, reaching the upper limit x = .66, corresponding to Ag₂SnSe₃. The parameters $\text{a}\text{= 5.677 ± .003}\text{A}\text{?}$ and $\text{a}\text{= 5.640 ± .004}\text{A}\text{?}$ were found respectively for AgSnSe₂ and Ag₂SnSe₃. Cubic AgSnS₂ was formed at 65 Kbars and 1200°C with $\text{a}\text{= 5.506 ± .002}\text{A}\text{?}$. The crystal structures calculated for AgSnS₂ and AgSnSe₂ (high pressure compound) yield respectively to R = .06 and R = .04 for a rock salt structure hypothesis.