Metal sulfides, polysulfides, polyselenides and polytellurides Sulfides |
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date: 12-3-2017
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Date: 26-11-2018
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Date: 10-12-2018
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Metal sulfides, polysulfides, polyselenides and polytellurides Sulfides
The group 1 and 2 metal sulfides possess the antifluorite and NaCl lattices respectively and appear to be typical ionic salts. However, the adoption of the NaCl lattice (e.g. by PbS and MnS) cannot be regarded as a criterion for ionic character. Most d-block metal monosulfides crystallize with the NiAs lattice (e.g. FeS, CoS, NiS) or the zinc blende or wurtzite structure (e.g. ZnS, CdS, HgS). Metal disulfides may adopt the CdI2 lattice (e.g. TiS2 and SnS2 with metal(IV) centres), but others such as FeS2 (iron pyrites) contain [S2]2- ions. The latter are formally analogous to peroxides and may be considered to be salts of H2S2. The blue paramagnetic [S2]- ion is an analogue of the superoxide ion and has been detected in solutions of alkali metal sulfides in acetone or dimethyl sulfoxide. Simple salts containing [S2]_ are not known, but the blue colour of the silicate mineral ultramarine is due to the presence of the radical anions [S2]- and [S3]-
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دراسة يابانية لتقليل مخاطر أمراض المواليد منخفضي الوزن
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اكتشاف أكبر مرجان في العالم قبالة سواحل جزر سليمان
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اتحاد كليات الطب الملكية البريطانية يشيد بالمستوى العلمي لطلبة جامعة العميد وبيئتها التعليمية
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