Spryite, gic.com/appservices/search">\({\text{Ag}}_{8}\left({{\text{As}}_{0.5}^{3 +} {\text{As}}_{0.5}^{5 +}}\right){\text{S}}_{6}\) : structure determination and inferred absence of superionic conduct

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• 作者：Luca Bindi ; Frank N. Keutsch ; Marta Morana…
• 关键词：Argyrodite ; Fast ionic conductors ; Crystal structure ; Ag ; sulfosalts
• 刊名：Physics and Chemistry of Minerals
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：44
• 期：1
• 页码：75-82
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Mineralogy; Crystallography and Scattering Methods; Geochemistry; Mineral Resources;
• 出版者：Springer Berlin Heidelberg
• ISSN：1432-2021
• 卷排序：44

文摘

We report data on the composition and crystal structure of the first As3+-bearing natural argyrodite, spryite. Spryite has the formula \(({{\text{Ag}}_{7.98} {\text{Cu}}_{0.05}})_{\varSigma = 8.03} ({{\text{As}}_{0.31}^{5 +} {\text{Ge}}_{0.36} {\text{As}}_{0.31}^{3 +} {\text{Fe}}_{0.02}^{3 +}})_{\varSigma = 1.00} {\text{S}}_{5.97}\), ideally \({\text{Ag}}_{8} ({{\text{As}}_{0.5}^{3 +} {\text{As}}_{0.5}^{5 +}}){\text{S}}_{6}\). The crystal studied was found in a sample from the Uchucchacua polymetallic deposit, Oyon district, Cajatambo, Lima Department, Peru. The structure was refined in the space group Pna2₁ up to R = 0.0782 using 2099 observed reflections [2σ(I) level]. Spryite is intimately twinned with six twin domains. The structure solution showed that As3+ and As5+ coexist in the new mineral, which represents the first case ever discovered in either a mineral or a synthetic compound belonging to a sulfide/sulfosalt group. High-temperature in situ X-ray diffraction experiments indicated that no phase transitions occur in the temperature range investigated and that the mineral does not show any evidence of fast ionic conduction.