Materials Data on Ca2Zr(SiO3)4 by Materials Project
Ca2ZrSi4O12 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to eight O2- atoms to form CaO8 hexagonal bipyramids that share corners with two equivalent SiO4 tetrahedra, edges with two equivalent ZrO6 octahedra, and edges with four SiO4 tetrahedra. There are a spread of Ca–O bond distances ranging from 2.35–2.67 Å. In the second Ca2+ site, Ca2+ is bonded in a 5-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.37–2.87 Å. Zr4+ is bonded to six O2- atoms to form ZrO6 octahedra that share corners with six SiO4 tetrahedra and edges with two equivalent CaO8 hexagonal bipyramids. There are a spread of Zr–O bond distances ranging from 2.09–2.14 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one CaO8 hexagonal bipyramid, a cornercorner with one ZrO6 octahedra, corners with two SiO4 tetrahedra, and an edgeedge with one CaO8 hexagonal bipyramid. The corner-sharing octahedral tilt angles are 27°. There are a spread of Si–O bond distances ranging from 1.60–1.69 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent ZrO6 octahedra, corners with two SiO4 tetrahedra, and an edgeedge with one CaO8 hexagonal bipyramid. The corner-sharing octahedra tilt angles range from 27–45°. There are a spread of Si–O bond distances ranging from 1.62–1.65 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+, one Zr4+, and one Si4+ atom. In the second O2- site, O2- is bonded in a trigonal planar geometry to two Ca2+ and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Zr4+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+ and two Si4+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+, one Zr4+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+ and two equivalent Si4+ atoms. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ca2+ and two equivalent Si4+ atoms.