Kobayashi Makoto, Yasunaga Takuya, Kato Hideki, Fujii Kotaro, Yashima Masatomo, Kakihana Masato
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1-W4-17, Ookayama, Meguro-ku, To-kyo 152-8551, Japan.
Acta Crystallogr E Crystallogr Commun. 2019 Jan 25;75(Pt 2):260-263. doi: 10.1107/S2056989019001257. eCollection 2019 Feb 1.
Single crystals of the solid solution series Ca Y SiO N were obtained by a solid-state reaction method using a flux for = 0, 0.5 and 1, resulting in CaYSiON (tetra-calcium triyttrium hepta-silicon oxynitride), CaYSiON and CaYSiON (penta-calcium diyttrium hepta-silicon oxynitride). Single-crystal X-ray analysis revealed that the three compounds are isotypic and belong to space-group type 6/. Ca and Y cations are distributed over two crystallographic sites (site symmetry .. and 1) in a disordered manner. The corresponding (Ca,Y)-centred polyhedra are connected by edge-sharing, resulting in the formation of a layer structure extending parallel to (001). Three [Si(O,N)] tetra-hedra (two with point group symmetry .., one with 3.. and half-occupancy) are condensed into an isolated [Si(O,N)] unit, in which an [Si(O,N)] tetra-hedron is located at the center of a 12-membered oxynitride ring with composition [SiON]. The present compounds are the first to have such an [Si(O,N)] unit in their structures.
通过使用助熔剂的固态反应法，获得了固溶体系列CaxY3−xSi7O1−xNx+3（x = 0、0.5和1）的单晶，得到了Ca4Y3Si7O1N4（四钙三钇七硅氧氮化物）、Ca4.5Y2.5Si7O0.5N4.5和Ca5Y2Si7O0N5（五钙二钇七硅氧氮化物）。单晶X射线分析表明，这三种化合物是同型的，属于空间群类型6/m。Ca和Y阳离子以无序方式分布在两个晶体学位置（位置对称性..m和1）上。相应的（Ca，Y）中心多面体通过边共享相连，形成了平行于（001）延伸的层状结构。三个[Si（O，N）4]四面体（两个具有点群对称性..m，一个具有3m.m，占据率为一半）缩合形成一个孤立的[Si3（O，N）10]单元，其中一个[Si（O，N）4]四面体位于组成[Si12O12N12]的12元氧氮环的中心。目前的化合物是首批在其结构中具有这种[Si3（O，N）10]单元的化合物。
