More Than 50 Years after Its Discovery in SiO2 Octahedral Coordination Has Also Been Established in SiS2 at High Pressure
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- 作者：Jürgen EversLeonhard Möckl ; Gilbert Oehlinger ; Ralf Köppe ; Hansgeorg Schnöckel ; Oleg Barkalov ; Sergey Medvedev ; Pavel Naumov
- 刊名：Inorganic Chemistry
- 出版年：2017
- 出版时间：January 3, 2017
- 年：2017
- 卷：56
- 期：1
- 页码：372-377
- 全文大小：313K
- ISSN：1520-510X
文摘
SiO<sub>2sub> exhibits a high-pressure–high-temperature polymorphism, leading to an increase in silicon coordination number and density. However, for the related compound SiS<sub>2sub> such pressure-induced behavior has not been observed with tetrahedral coordination yet. All four crystal structures of SiS<sub>2sub> known so far contain silicon with tetrahedral coordination. In the orthorhombic, ambient-pressure phase these tetrahedra share edges and achieve only low space filling and density. Up to 4 GPa and 1473 K, three phases can be quenched as metastable phases from high-pressure high-temperature to ambient conditions. Space occupancy and density are increased first by edge and corner sharing and then by corner sharing alone. The structural situation of SiS<sub>2sub> up to the current study resembles that of SiO<sub>2sub> in 1960: Then, in its polymorphs only Si–O<sub>4sub> tetrahedra were known. But in 1961, a polymorph with rutile structure was discovered: octahedral Si-O<sub>6sub> coordination was established. Now, 50 years later, we report here on the transition from 4-fold to 6-fold coordination in SiS<sub>2sub>, the sulfur analogue of silica.