Materials Data on Ca3Al4SiO12 by Materials Project

Ca3Al4SiO12 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are three inequivalent Ca sites. In the first Ca site, Ca is bonded to six O atoms to form CaO6 octahedra that share a cornercorner with one SiO4 tetrahedra, corners with three AlO4 tetrahedra, edges with three equivalent CaO6 octahedra, and edges with three equivalent AlO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.24–2.34 Å. In the second Ca site, Ca is bonded to six O atoms to form CaO6 octahedra that share a cornercorner with one SiO4 tetrahedra, corners with three AlO4 tetrahedra, edges with three equivalent CaO6 octahedra, and edges with three equivalent AlO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.23–2.33 Å. In the third Ca site, Ca is bonded to six O atoms to form CaO6 octahedra that share corners with three equivalent SiO4 tetrahedra and corners with nine AlO4 tetrahedra. There are a spread of Ca–O bond distances ranging from 2.37–2.96 Å. There are four inequivalent Al sites. In the first Al site, Al is bonded to six O atoms to form AlO6 octahedra that share a cornercorner with one SiO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with six CaO6 octahedra. There are a spread of Al–O bond distances ranging from 1.84–2.12 Å. In the second Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share a cornercorner with one AlO6 octahedra, corners with five CaO6 octahedra, and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–73°. There is one shorter (1.77 Å) and three longer (1.81 Å) Al–O bond length. In the third Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share a cornercorner with one AlO6 octahedra, corners with five CaO6 octahedra, and corners with three equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–66°. There is one shorter (1.78 Å) and three longer (1.80 Å) Al–O bond length. In the fourth Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share a cornercorner with one AlO6 octahedra, corners with five CaO6 octahedra, and corners with three equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–66°. There is one shorter (1.79 Å) and three longer (1.80 Å) Al–O bond length. Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one AlO6 octahedra, corners with five CaO6 octahedra, and corners with three equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–66°. There is two shorter (1.66 Å) and two longer (1.67 Å) Si–O bond length. There are twelve inequivalent O sites. In the first O site, O is bonded in a rectangular see-saw-like geometry to two Ca, one Al, and one Si atom. In the second O site, O is bonded in a distorted rectangular see-saw-like geometry to two Ca and two Al atoms. In the third O site, O is bonded in a rectangular see-saw-like geometry to two Ca and two Al atoms. In the fourth O site, O is bonded in a distorted rectangular see-saw-like geometry to two Ca and two Al atoms. In the fifth O site, O is bonded in a 3-coordinate geometry to one Ca, one Al, and one Si atom. In the sixth O site, O is bonded in a 2-coordinate geometry to one Ca, one Al, and one Si atom. In the seventh O site, O is bonded in a trigonal planar geometry to one Ca and two Al atoms. In the eighth O site, O is bonded in a trigonal planar geometry to one Ca and two Al atoms. In the ninth O site, O is bonded in a distorted T-shaped geometry to two Ca and one Al atom. In the tenth O site, O is bonded in a distorted trigonal non-coplanar geometry to two Ca and one Al atom. In the eleventh O site, O is bonded in a distorted trigonal planar geometry to one Ca, one Al, and one Si atom. In the twelfth O site, O is bonded in a trigonal planar geometry to one Ca and two Al atoms.

Ca₃Al₄SiO₁₂结晶于三斜晶系P1空间群，其结构为三维网状结构。该体系存在3个非等效的Ca位点：
在第一个Ca位点中，Ca与6个O原子配位形成CaO₆八面体，该八面体与1个SiO₄四面体共享1个角顶，与3个AlO₄四面体共享角顶，与3个等价的CaO₆八面体共享棱边，同时与3个等价的AlO₆八面体共享棱边。Ca-O键的键长分布范围为2.24~2.34 Å。
在第二个Ca位点中，Ca与6个O原子配位形成CaO₆八面体，该八面体与1个SiO₄四面体共享1个角顶，与3个AlO₄四面体共享角顶，与3个等价的CaO₆八面体共享棱边，同时与3个等价的AlO₆八面体共享棱边。Ca-O键的键长分布范围为2.23~2.33 Å。
在第三个Ca位点中，Ca与6个O原子配位形成CaO₆八面体，该八面体与3个等价的SiO₄四面体共享角顶，同时与9个AlO₄四面体共享角顶。Ca-O键的键长分布范围为2.37~2.96 Å。
该体系存在4个非等效的Al位点：
在第一个Al位点中，Al与6个O原子配位形成AlO₆八面体，该八面体与1个SiO₄四面体共享1个角顶，与3个AlO₄四面体共享角顶，同时与6个CaO₆八面体共享棱边。Al-O键的键长分布范围为1.84~2.12 Å。
在第二个Al位点中，Al与4个O原子配位形成AlO₄四面体，该四面体与1个AlO₆八面体共享1个角顶，与5个CaO₆八面体共享角顶，同时与3个等价的SiO₄四面体共享角顶。共享角顶的八面体倾斜角范围为47°~73°，该位点存在1条较短的Al-O键（1.77 Å）与3条较长的Al-O键（1.81 Å）。
在第三个Al位点中，Al与4个O原子配位形成AlO₄四面体，该四面体与1个AlO₆八面体共享1个角顶，与5个CaO₆八面体共享角顶，同时与3个等价的AlO₄四面体共享角顶。共享角顶的八面体倾斜角范围为49°~66°，该位点存在1条较短的Al-O键（1.78 Å）与3条较长的Al-O键（1.80 Å）。
在第四个Al位点中，Al与4个O原子配位形成AlO₄四面体，该四面体与1个AlO₆八面体共享1个角顶，与5个CaO₆八面体共享角顶，同时与3个等价的AlO₄四面体共享角顶。共享角顶的八面体倾斜角范围为50°~66°，该位点存在1条较短的Al-O键（1.79 Å）与3条较长的Al-O键（1.80 Å）。
Si与4个O原子配位形成SiO₄四面体，该四面体与1个AlO₆八面体共享1个角顶，与5个CaO₆八面体共享角顶，同时与3个等价的AlO₄四面体共享角顶。共享角顶的八面体倾斜角范围为49°~66°，该位点存在2条较短的Si-O键（1.66 Å）与2条较长的Si-O键（1.67 Å）。
该体系存在12个非等效的O位点：
第一个O位点中，O原子以矩形跷跷板状配位构型与2个Ca、1个Al及1个Si原子结合。
第二个O位点中，O原子以畸变矩形跷跷板状配位构型与2个Ca及2个Al原子结合。
第三个O位点中，O原子以矩形跷跷板状配位构型与2个Ca及2个Al原子结合。
第四个O位点中，O原子以畸变矩形跷跷板状配位构型与2个Ca及2个Al原子结合。
第五个O位点中，O原子以三配位构型与1个Ca、1个Al及1个Si原子结合。
第六个O位点中，O原子以双配位构型与1个Ca、1个Al及1个Si原子结合。
第七个O位点中，O原子以三角平面配位构型与1个Ca及2个Al原子结合。
第八个O位点中，O原子以三角平面配位构型与1个Ca及2个Al原子结合。
第九个O位点中，O原子以畸变T型配位构型与2个Ca及1个Al原子结合。
第十个O位点中，O原子以畸变非共面三角配位构型与2个Ca及1个Al原子结合。
第十一个O位点中，O原子以畸变三角平面配位构型与1个Ca、1个Al及1个Si原子结合。
第十二个O位点中，O原子以三角平面配位构型与1个Ca及2个Al原子结合。