Synthetic Gold Chalcogenides in the Au–Te–Se–S System and Their Natural Analogs

Quaternary chalcogenides of AuX (AuTe 0.7 Se 0.2 S 0.1 ), Au 3 X 10 (Au 3 Te 6 Se 3 S, Au 3 Te 6 Se 2.5 S 1.5 ), and AuX 2 (AuTe 1.8 Se 0.2 , AuTe 1.8 Se 0.1 S 0.1 ) composition were synthesized for the first time in the Au‒Te‒Se‒S system, where Te ≥ Se + S. They are produced by dry synthesis upon heating a mixture of elementary substances with compositions of AuTe 0.666 Se 0.167 S 0.167 (X/Au = 1, X = Σ(Te + Se + S)), AuTeSe 0.5 S 0.5 (X/Au = 2), AuTe 2 Se 1.125 S 0.375 , AuTe 2 Se 0.75 S 0.75 (X/Au = 3.5), and AuTe 2.5 SeS 0.5 (X/Au = 4) in vacuum quartz ampoules from 25–700°C and annealing at 400°C. According to XRD, the synthetic Au chalcogenides of AuTe 1.8 (Se,S) 0.2 composition correspond to calaverite (α-AuTe 2 ). The unidentified XRD peaks belong to AuX and Au 3 X 10 . They are synthetic analogs of previously unknown natural compounds, which were found in the Gaching area of the Maletoivayam ore field (Central Kamchatka volcanic belt). The compositions of natural phases span the following ranges: Au 0.99–1.00 Te 0.70–0.71 Se 0.25–0.27 S 0.03–0.06 and Au 2.91–3.08 Te 5.85–6.06 Se 1.57–3.66 S 2.63–0.44 . The Raman spectra of synthetic and natural Au chalcogendies close in composition are identical.