DOI: 10.17188/1677301
title: Materials Data on K2Na4Ca5(Si6O17)2 by Materials Project

description: K2Na4Ca5(Si6O17)2 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of K–O bond distances ranging from 2.66–3.21 Å. In the second K site, K is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of K–O bond distances ranging from 2.83–3.41 Å. There are four inequivalent Na sites. In the first Na site, Na is bonded to five O atoms to form distorted NaO5 trigonal bipyramids that share a cornercorner with one CaO6 octahedra, corners with four SiO4 tetrahedra, and edges with two equivalent CaO6 octahedra. The corner-sharing octahedral tilt angles are 29°. There are a spread of Na–O bond distances ranging from 2.43–2.79 Å. In the second Na site, Na is bonded in a distorted see-saw-like geometry to four O atoms. There are a spread of Na–O bond distances ranging from 2.34–2.54 Å. In the third Na site, Na is bonded in a 5-coordinate geometry to five O atoms. There are a spread of Na–O bond distances ranging from 2.17–2.92 Å. In the fourth Na site, Na is bonded in a 4-coordinate geometry to four O atoms. There are two shorter (2.26 Å) and two longer (2.67 Å) Na–O bond lengths. There are three inequivalent Ca sites. In the first Ca site, Ca is bonded to six O atoms to form CaO6 octahedra that share corners with four SiO4 tetrahedra, a cornercorner with one NaO5 trigonal bipyramid, and edges with two equivalent CaO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.35–2.50 Å. In the second Ca site, Ca is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ca–O bond distances ranging from 2.19–2.71 Å. In the third Ca site, Ca is bonded to six O atoms to form CaO6 octahedra that share corners with four SiO4 tetrahedra, edges with three CaO6 octahedra, and an edgeedge with one NaO5 trigonal bipyramid. There are a spread of Ca–O bond distances ranging from 2.35–2.50 Å. There are eight inequivalent Si sites. In the first 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 48°. There is two shorter (1.62 Å) and two longer (1.66 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 two CaO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–58°. There are a spread of Si–O bond distances ranging from 1.63–1.68 Å. In the third 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 1.61–1.66 Å. In the fourth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent CaO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 80°. There are a spread of Si–O bond distances ranging from 1.61–1.67 Å. In the fifth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one CaO6 octahedra, corners with three SiO4 tetrahedra, and a cornercorner with one NaO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 63°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the sixth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three SiO4 tetrahedra and a cornercorner with one NaO5 trigonal bipyramid. There are a spread of Si–O bond distances ranging from 1.58–1.69 Å. In the seventh 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 octahedral tilt angles are 60°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the eighth 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 1.63–1.65 Å. There are twenty-four inequivalent O sites. In the first O site, O is bonded in a distorted rectangular see-saw-like geometry to one Na, two Ca, and one Si atom. In the second O site, O is bonded in a 3-coordinate geometry to two Ca and one Si atom. In the third O site, O is bonded in a distorted bent 150 degrees geometry to one K and two Si atoms. In the fourth O site, O is bonded in a distorted water-like geometry to one K, one Na, and two Si atoms. In the fifth O site, O is bonded in a distorted bent 150 degrees geometry to one K and two equivalent Si atoms. In the sixth O site, O is bonded in a 3-coordinate geometry to one K and two equivalent Si atoms. In the seventh O site, O is bonded in a bent 150 degrees geometry to 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 distorted bent 150 degrees geometry to one K and two Si atoms. In the tenth O site, O is bonded in a bent 150 degrees geometry to one Na and one Si atom. In the eleventh O site, O is bonded in a distorted trigonal planar geometry to two equivalent Ca and one Si atom. In the twelfth O site, O is bonded in a 1-coordinate geometry to one K, two equivalent Ca, and one Si atom. In the thirteenth O site, O is bonded in a 3-coordinate geometry to one K, two equivalent Ca, and one Si atom. In the fourteenth O site, O is bonded in a distorted single-bond geometry to one K, two equivalent Ca, and one Si atom. In the fifteenth O site, O is bonded in a distorted bent 150 degrees geometry to one K and two Si atoms. In the sixteenth O site, O is bonded in a distorted trigonal planar geometry to one K, one Na, and one Si atom. In the seventeenth O site, O is bonded to two Na, one Ca, and one Si atom to form distorted ONa2CaSi tetrahedra that share corners with two equivalent ONa2CaSi tetrahedra and a cornercorner with one ONaCa3 trigonal pyramid. In the eighteenth O site, O is bonded in a 2-coordinate geometry to one Ca and two Si atoms. In the nineteenth O site, O is bonded in a see-saw-like geometry to one Na and three Ca atoms. In the twentieth O site, O is bonded in a distorted see-saw-like geometry to two Na and two equivalent Ca atoms. In the twenty-first O site, O is bonded to one Na and three Ca atoms to form distorted corner-sharing ONaCa3 trigonal pyramids. In the twenty-second O site, O is bonded in a distorted single-bond geometry to two Na, two equivalent Ca, and one Si atom. In the twenty-third O site, O is bonded in a 2-coordinate geometry to one K and two equivalent Si atoms. In the twenty-fourth O site, O is bonded in a 2-coordinate geometry to one Na and two equivalent Si atoms.