High temperature neutron powder diffraction study of the Cu12Sb4S13 and Cu4Sn7S16 phases

In situ neutron powder diffraction data (heating rate of 2.5 K/min) indicates that (i) the ternary Cu12Sb4S13 phase is stable up to 792 K and decomposes at higher temperature into Cu3SbS3 and Cu1.5Sb0.5S2, and (ii) the Cu4Sn7S16 phase is stable up to 891 K and decomposes at higher temperature into Sn2S3 and a cubic phase of sphalerite ZnS-type structure. Sulfur volatilization likely occurs in order to balance the overall stoichiometry.282