R2: Crystal structure, crystal chemistry, physical properties of minerals, crystal growth and applied mineralogy

[R2-05] Crystal chemistry of Au_1-xAg_xTe₂ minerals: structure analyses krennerite (x=0.13) and sylvanite (x=0.32)

[Presentation award entry]

*Ginga Kitahara¹, Akira Yoshiasa¹, Hidetomo Hongu¹, Makoto Tokuda², Kazumasa Sigiyama², Koichi Momma³, Ritsuro Miyawaki³ (1. Kumamoto Univ. Sci., 2. Tohoku Univ. IMR, 3. National Museum)

Keywords:krennerite, sylvanite, single crystal diffraction, XAFS, chemical formula

The structures analyses on krennerite (Au_0.87Ag_0.13Te₂) and sylvanite (Au_0.68Ag_0.32Te₂) were performed using single crystal X-ray diffraction and XAFS (X-ray absorption fine structure) experiments. The chemical formula of krennerite and sylvanite can be expressed as Au³⁺₂(Au¹⁺_2-xAg¹⁺_x)[Te₃]^2-[Te₂]^2-₂Te^2-, and Au³⁺(Au¹⁺_1-xAg¹⁺_x) [Te₂]^2-₂, respectively.