Synthesis, crystal structure, and phase relations of AlSiO3OH, a high-pressure hydrous phase
Synthesis, crystal structure, and phase relations of AlSiO3OH, a high-pressure hydrous phase
复制标题
DOI：
10.2138/am-1998-7-820
复制
发表时间：
1998-08
影响因子：
3.1
通讯作者：
M. Schmidt;L. Finger;R. Angel;R. Dinnebier
中科院分区：
文献类型：
--
作者：
M. Schmidt;L. Finger;R. Angel;R. Dinnebier
合成了Eggleton等（1978）首次描述的相蛋，并确定其组成为AlSiO 3OH。通过高分辨X射线粉末衍射分析，确定了AlSiO_3OH的晶体结构，包括氢原子的位置。由此得到的晶格常数为a = 7.14409（2）°，B = 4.33462（1）°，c = 6.95253（2）°，β = 98.396（1）°。空间群为P21\n; Z = 4，V0 = 212.99（1）<$3，零压密度为3.74 g/cm 3。该相在11 GPa以上、700 ℃时出现，具有锑钾云母结构的共同特征。AlSiO_3 OH是由黄玉-OH生成的，在17.7GPa和1300 ℃下仍能保持。从Schreinemaker分析，我们预测相蛋分解与压力未知，可能是水合铝硅酸盐。潜在的，相蛋可以取代黄玉-OH或蓝晶石在俯冲地壳的整体组成，并可能运输到地球深部的一些水。
Abstract Phase egg, first described by Eggleton et al. (1978), was synthesized and its composition determined to be AlSiO3OH. The crystal structure of AlSiO3OH, including the position of the hydrogen, has been solved and refined from high-resolution X-ray powder diffraction. The resulting lattice constants are a = 7.14409(2) Å, b = 4.33462(1) Å, c = 6.95253(2) Å, and β = 98.396(1)°. The space group is P21\n; Z = 4, V0 = 212.99(1) Å3, and the zero pressure density is 3.74 g/cm3. This phase, which has features in common with the sti-shovite structure, occurs above 11 GPa and 700 ℃. AlSiO3OH forms from topaz-OH with increasing pressure and persists to more than 17.7 GPa and 1300 ℃. From a Schreinemaker analysis, we predicted that phase egg decomposes with pressure to an unknown, possibly hydrous aluminosilicate. Potentially, phase egg could replace topaz-OH or kyanite in subducted crustal bulk compositions and may transport some water into the deep Earth.