Electron microscopic studies of modulated structures in (Au,Ag)Te 2. III. Krennerite

The structure of krennerite (Au _0.8Ag _0.2Te ₂) as determined using X-ray diffraction, is confirmed by means of electron diffraction and high resolution electron microscopy. The structure can be considered as a twin interface modulated long period superstructure of calaverite. The images suggest that gold and silver are ordered, silver being preferentially located along the twin interface. Planar defects associated with variable width of the twin lamellae are discussed in detail and a structural model can be deduced from the high resolution observations.