Materials Data on NaCa2(SiO3)3 by Materials Project
NaCa2(SiO3)3 is Esseneite-like structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Na is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Na–O bond distances ranging from 2.35–2.61 Å. There are two inequivalent Ca sites. In the first Ca site, Ca is bonded to six O atoms to form CaO6 octahedra that share corners with six SiO4 tetrahedra and edges with four CaO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.34–2.45 Å. In the second Ca site, Ca is bonded to six O atoms to form CaO6 octahedra that share corners with six SiO4 tetrahedra and edges with four CaO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.32–2.45 Å. There are three inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with four CaO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 37–64°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with four CaO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–66°. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with four CaO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 48–58°. There are a spread of Si–O bond distances ranging from 1.61–1.69 Å. There are nine inequivalent O sites. In the first O site, O is bonded in a distorted trigonal planar geometry to two Ca and one Si atom. In the second O site, O is bonded in a distorted rectangular see-saw-like geometry to one Na, two Ca, and one Si atom. In the third O site, O is bonded in a distorted T-shaped geometry to one Na, one Ca, and one Si atom. In the fourth O site, O is bonded in a 3-coordinate geometry to one Na, one Ca, and one Si atom. In the fifth O site, O is bonded to three Ca and one Si atom to form a mixture of distorted edge and corner-sharing OCa3Si tetrahedra. In the sixth O site, O is bonded to three Ca and one Si atom to form a mixture of distorted edge and corner-sharing OCa3Si tetrahedra. In the seventh O site, O is bonded in a 2-coordinate geometry to one Na and two Si atoms. In the eighth O site, O is bonded in a 2-coordinate geometry to one Na and two Si atoms. In the ninth O site, O is bonded in a distorted T-shaped geometry to one Na and two Si atoms.