Materials Data on Mg3Si4O13 by Materials Project

(Mg3Si4O12)2O2 crystallizes in the monoclinic Cm space group. The structure is two-dimensional and consists of two water molecules and one Mg3Si4O12 sheet oriented in the (0, 0, 1) direction. In the Mg3Si4O12 sheet, there are two inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four SiO4 tetrahedra and edges with six MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.02–2.15 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four SiO4 tetrahedra and edges with six equivalent MgO6 octahedra. There are two shorter (2.06 Å) and four longer (2.11 Å) Mg–O bond lengths. There are two inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–58°. There is two shorter (1.64 Å) and two longer (1.65 Å) Si–O bond length. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–58°. All Si–O bond lengths are 1.64 Å. There are eight inequivalent O sites. In the first O site, O is bonded in a bent 150 degrees geometry to two equivalent Si atoms. In the second O site, O is bonded in a bent 150 degrees geometry to two equivalent Si atoms. In the third O site, O is bonded in a bent 150 degrees geometry to two equivalent Si atoms. In the fourth O site, O is bonded in a bent 150 degrees geometry to two equivalent Si atoms. In the fifth O site, O is bonded in a rectangular see-saw-like geometry to three Mg and one Si atom. In the sixth O site, O is bonded in a distorted rectangular see-saw-like geometry to three Mg and one Si atom. In the seventh O site, O is bonded in a trigonal non-coplanar geometry to three Mg atoms. In the eighth O site, O is bonded in a trigonal non-coplanar geometry to three Mg atoms.

(Mg₃Si₄O₁₂)₂O₂晶体属于单斜晶系Cm空间群。该材料为二维结构，包含两个水分子与一片沿(0, 0, 1)晶向取向的Mg₃Si₄O₁₂片层。在Mg₃Si₄O₁₂片层中存在两类非等价镁位点。第一类镁位点中，镁原子与六个氧原子配位形成MgO₆八面体，该八面体与四个SiO₄四面体共顶角，同时与六个MgO₆八面体共棱；镁-氧键的键长分布范围为2.02~2.15 Å。第二类镁位点中，镁原子同样与六个氧原子配位形成MgO₆八面体，该八面体与四个SiO₄四面体共顶角，且与六个等价的MgO₆八面体共棱，其镁-氧键包含两个较短键长（2.06 Å）与四个较长键长（2.11 Å）。该结构存在两类非等价硅位点。第一类硅位点中，硅原子与四个氧原子配位形成SiO₄四面体，该四面体与三个MgO₆八面体及三个等价的SiO₄四面体共顶角，共顶角八面体的倾斜角范围为56°~58°，硅-氧键包含两个较短键长（1.64 Å）与两个较长键长（1.65 Å）。第二类硅位点中，硅原子同样与四个氧原子配位形成SiO₄四面体，该四面体与三个MgO₆八面体及三个等价的SiO₄四面体共顶角，共顶角八面体的倾斜角范围为56°~58°，所有硅-氧键的键长均为1.64 Å。该结构存在八类非等价氧位点。第一类氧位点中，氧原子以150°弯曲配位构型与两个等价的硅原子配位；第二类至第四类氧位点的配位环境与第一类氧位点完全一致。第五类氧位点中，氧原子以矩形跷跷板状配位几何与三个镁原子及一个硅原子配位。第六类氧位点中，氧原子以畸变矩形跷跷板状配位几何与三个镁原子及一个硅原子配位。第七类与第八类氧位点中，氧原子均以三角非共面配位几何与三个镁原子配位。