Materials Data on CaMg(SiO3)2 by Materials Project

CaMgSi2O6 is Esseneite structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six equivalent SiO4 tetrahedra and edges with two equivalent CaO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.29–2.48 Å. Mg2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There is two shorter (1.95 Å) and two longer (2.02 Å) Mg–O bond length. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent CaO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 40–66°. There are a spread of Si–O bond distances ranging from 1.62–1.67 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Mg2+, and one Si4+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ca2+, one Mg2+, and one Si4+ atom.

CaMgSi₂O₆属于陨钙镁辉石（Esseneite）结构，结晶于单斜晶系C2/c空间群。该结构为三维框架结构。Ca²+与六个O²-配位形成CaO₆八面体，该八面体与六个等价的SiO₄四面体共享顶点，同时与两个等价的CaO₆八面体共享棱边。Ca-O键的键长分布范围为2.29~2.48 Å。Mg²+以矩形跷跷板状配位几何与四个O²-配位，其Mg-O键长分为两组：两个较短的键长为1.95 Å，另外两个较长的键长为2.02 Å。Si⁴+与四个O²-配位形成SiO₄四面体，该四面体与三个等价的CaO₆八面体共享顶点，同时与两个等价的SiO₄四面体共享顶点。共享顶点的八面体倾斜角范围为40°~66°。Si-O键的键长分布范围为1.62~1.67 Å。体系中存在三个不等价的O²-位点。在第一个O²-位点中，O²-以三配位几何分别与一个Ca²+、一个Mg²+以及一个Si⁴+配位。在第二个O²-位点中，O²-以150°弯曲配位几何与两个等价的Si⁴+配位。在第三个O²-位点中，O²-以畸变矩形跷跷板状配位几何分别与两个等价的Ca²+、一个Mg²+以及一个Si⁴+配位。