DOI: 10.17188/1736977
title: Materials Data on K2CaSi4O15 by Materials Project

description: K2CaSi4O15 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of two K2CaSi4O15 sheets oriented in the (0, 0, 1) direction. there are two inequivalent K sites. In the first K site, K is bonded in a 6-coordinate geometry to six O atoms. There are a spread of K–O bond distances ranging from 2.62–3.04 Å. In the second K site, K is bonded in a 5-coordinate geometry to six O atoms. There are a spread of K–O bond distances ranging from 2.76–3.12 Å. Ca is bonded to six O atoms to form CaO6 octahedra that share corners with five SiO4 tetrahedra and edges with two equivalent CaO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.35–2.69 Å. There are four inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent CaO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–58°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent CaO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–59°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one CaO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 65°. There are a spread of Si–O bond distances ranging from 1.61–1.67 Å. In the fourth Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.56–1.69 Å. There are fifteen inequivalent O sites. In the first O site, O is bonded in a 1-coordinate geometry to one K, two equivalent Ca, and one Si atom. In the second O site, O is bonded in a 2-coordinate geometry to two K and two Si atoms. In the third O site, O is bonded in a 1-coordinate geometry to one K, two equivalent Ca, and one Si atom. In the fourth O site, O is bonded in a single-bond geometry to one Si atom. In the fifth O site, O is bonded in a distorted bent 150 degrees geometry to one K and two Si atoms. In the sixth O site, O is bonded in a distorted single-bond geometry to one Ca, one Si, and one O atom. The O–O bond length is 1.48 Å. In the seventh O site, O is bonded in a distorted bent 150 degrees geometry to one K and two Si atoms. In the eighth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the ninth O site, O is bonded in a 2-coordinate geometry to one K and two Si atoms. In the tenth O site, O is bonded in a distorted bent 150 degrees geometry to one K and two Si atoms. In the eleventh O site, O is bonded in a 2-coordinate geometry to one K, one Ca, and one O atom. In the twelfth O site, O is bonded in a single-bond geometry to one O atom. The O–O bond length is 1.24 Å. In the thirteenth O site, O is bonded in a distorted bent 120 degrees geometry to one K and one O atom. In the fourteenth O site, O is bonded in a distorted single-bond geometry to one K and one O atom. The O–O bond length is 1.26 Å. In the fifteenth O site, O is bonded in an L-shaped geometry to one K and one O atom.