Structures of minerals with OH attached to Si and their properties.

1.利用X射线单晶反采集数据，采用最小二乘法对日本群马县三叶川富铝云母的晶体结构进行了精细化。根据差分傅里叶图确定了氢原子的位置，并与由键价计算得出的结果一致。该晶体具有如下特征：双四面体单元[Si2O6(OH)]具有直接与硅原子相连的氢氧化物基团；两种八面体晶位中的一种优先被铝离子占据；另一种八面体晶位既被二价离子占据，又被三价离子占据，后者的电荷由氢原子的数量组成。我们没有发现铁和锰的单晶。利用X-射线单晶衍射数据对日本福井县中松矿的P/NNC泡沫石进行了晶体结构的精炼。从键价计算，质子给体原子都是O(11)和O(10)。B位(方形金字塔)被Fe原子占据一半。3(1)利用X射线单晶衍射数据，对鳞石英和Ag3AsSe_3的晶体结构进行了修正。利用X射线单晶衍射数据，对斜方晶系鳞石英的结构随温度的变化进行了研究，并对高温鳞石英进行了高阶热运动张量分析。3(2)与金泽医科大学松井正则基于能量最小化的计算模型研究了高压相的结构和弹性性质。3(3)与德国Wondratschek合作研究了高压相的晶体轨道。导出了该平面的非特征轨道。

1. Refinement of the crystal structure of Al-rich pumpellyite from Sanbagawa, Gunma Prefecture, Japan, was carried out by a least squares method with X-ray single-crystal counter-collected data. The positions of hydrogen atoms have been determined based on the difference Fourier maps, and are consistent with the results deduced from bond-valence calculations. This crystal has the following characters: the double tetrahedral unit [Si_2O_6(OH)] characteristically has a hydroxide group directly attached to Si atom; one of two kinds of octahedral sites is occupied by an aluminum ion in preference to the others; the other octahedral site if occupied by both divalent and trivalent ions , and the electric charge of the latter site is compensted by the amount of hydrogen atoms. We could not find Fe and Mn single pumpellyite crystals.2. Refinement of the crystal structure of P/nnc-vesuvianite from Nakatatsu mine, Fukui Prefecture, Japan,was done using X-ray single - crystal diffraction data. From bond-valence calculations, the proton donor atoms are both O (11) and O (10). The B-sites(square pyramid ) are half occupied by Fe atoms3. Other studies related to this project.3(1) Crystal structure refinements tridymite and Ag_3AsSe_3. structural change of orthorhombic-I tridymite with temperature and high-order thermal motion tensor analyses of high temperature tridymite have been carried out using X-ray single -crystal diffraction data. The crystal structure of Ag_3AsSe_3 has been refined based on high-order thermal motion tensors.3(2) The structural and elastic properties of high-pressure phases of MgSiO_3 are investigated with a computational model based on energy minimization in collaboration with Masanori Matsui, Kanazawa Medical University.3(3) The crystallographic orbits have been studied in collaboration with Wondratschek, Germany. The non-characteristic orbits of the plane have been derived.