Haines J, Léger J M, Gorelli F, Hanfland M
Laboratoire de Physico-Chimie de la Matière Condensée, UMR CNRS 5617, Université Montpellier II Sciences et Techniques du Languedoc, cc 003, Place Eugène Bataillon, 34095 Montpellier cedex 5, France.
Phys Rev Lett. 2001 Oct 8;87(15):155503. doi: 10.1103/PhysRevLett.87.155503. Epub 2001 Sep 25.
alpha-quartz, which has been reported to undergo pressure-induced amorphization, was found to transform to a monoclinic, crystalline phase when compressed to 45 GPa at room temperature in a close to hydrostatic, helium pressure medium. The x-ray powder diffraction data obtained could be indexed based on a monoclinic cell, and the intensities are in agreement with a P2(1)/c model structure built up of 3x2 zigzag chains of SiO6 octahedra. This new polymorph of silica, which is metastable under ambient conditions, has been isolated for the first time and is one of several possible competing dense forms containing octahedrally coordinated silicon.
据报道会发生压力诱导非晶化的α-石英，在室温下于接近静水压力的氦压力介质中被压缩至45吉帕斯卡时，被发现转变为单斜晶系的结晶相。所获得的X射线粉末衍射数据可以根据单斜晶胞进行索引，其强度与由SiO6八面体的3x2锯齿链构成的P2(1)/c模型结构一致。这种二氧化硅的新多晶型物在环境条件下是亚稳的，首次被分离出来，并且是几种可能的含有八面体配位硅的竞争致密形式之一。
