DOI: 10.17188/1747994
title: Materials Data on Na4SrSi8O23 by Materials Project

description: Na4SrSi8O23 crystallizes in the monoclinic P2/c space group. The structure is three-dimensional. there are five inequivalent Na sites. In the first Na site, Na is bonded to six O atoms to form distorted NaO6 octahedra that share corners with four SiO4 tetrahedra and edges with four NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.34–2.79 Å. In the second Na site, Na is bonded to six O atoms to form distorted NaO6 octahedra that share corners with four SiO4 tetrahedra and edges with four equivalent NaO6 octahedra. There are two shorter (2.35 Å) and four longer (2.41 Å) Na–O bond lengths. In the third Na site, Na is bonded in a 5-coordinate geometry to six O atoms. There are a spread of Na–O bond distances ranging from 2.27–2.80 Å. In the fourth Na site, Na is bonded to six O atoms to form NaO6 octahedra that share corners with four SiO4 tetrahedra and edges with two equivalent SrO6 octahedra. There are a spread of Na–O bond distances ranging from 2.39–2.41 Å. In the fifth Na site, Na is bonded to six O atoms to form distorted NaO6 octahedra that share corners with four SiO4 tetrahedra and edges with two SiO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.49–2.56 Å. There are two inequivalent Sr sites. In the first Sr site, Sr is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Sr–O bond distances ranging from 2.54–3.11 Å. In the second Sr site, Sr is bonded to six O atoms to form distorted SrO6 octahedra that share corners with six SiO4 tetrahedra and edges with two equivalent NaO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.49–2.69 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 NaO6 octahedra and corners with four SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 59°. There are a spread of Si–O bond distances ranging from 1.62–1.64 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one SrO6 octahedra, corners with three SiO4 tetrahedra, and an edgeedge with one NaO6 octahedra. The corner-sharing octahedral tilt angles are 37°. There is one shorter (1.61 Å) and three longer (1.66 Å) Si–O bond length. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one SrO6 octahedra, corners with two NaO6 octahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–67°. There are a spread of Si–O bond distances ranging from 1.60–1.67 Å. In the fourth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two NaO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 66–70°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the fifth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one NaO6 octahedra, a cornercorner with one SrO6 octahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 46–60°. There are a spread of Si–O bond distances ranging from 1.61–1.67 Å. In the sixth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three NaO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 59–70°. There are a spread of Si–O bond distances ranging from 1.60–1.67 Å. In the seventh Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one NaO6 octahedra and corners with four SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. There is three shorter (1.63 Å) and one longer (1.64 Å) Si–O bond length. In the eighth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent NaO6 octahedra, corners with three SiO4 tetrahedra, and an edgeedge with one NaO6 octahedra. The corner-sharing octahedra tilt angles range from 68–71°. There are a spread of Si–O bond distances ranging from 1.60–1.67 Å. There are twenty-three inequivalent O sites. In the first O site, O is bonded in a distorted T-shaped geometry to three Na atoms. In the second O site, O is bonded in a distorted water-like geometry to two Na atoms. In the third O site, O is bonded in a single-bond geometry to one Na atom. In the fourth O site, O is bonded in a single-bond geometry to one Na atom. In the fifth O site, O is bonded in a bent 150 degrees geometry to one Sr and two Si atoms. In the sixth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the seventh O site, O is bonded in a bent 120 degrees geometry to two Si atoms. In the eighth O site, O is bonded in a distorted trigonal planar geometry to one Na and two Si atoms. In the ninth O site, O is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na, one Sr, and one Si atom. In the tenth O site, O is bonded in a 2-coordinate geometry to one Na and two Si atoms. In the eleventh O site, O is bonded in a 3-coordinate geometry to one Na and two Si atoms. In the twelfth O site, O is bonded in a 3-coordinate geometry to one Na and two Si atoms. In the thirteenth O site, O is bonded to two Na, one Sr, and one Si atom to form a mixture of distorted corner and edge-sharing ONa2SrSi tetrahedra. In the fourteenth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the fifteenth O site, O is bonded in a distorted bent 150 degrees geometry to two Si atoms. In the sixteenth O site, O is bonded to two Na, one Sr, and one Si atom to form a mixture of distorted corner and edge-sharing ONa2SrSi tetrahedra. In the seventeenth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the eighteenth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the nineteenth O site, O is bonded to two Na, one Sr, and one Si atom to form a mixture of distorted corner and edge-sharing ONa2SrSi tetrahedra. In the twentieth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the twenty-first O site, O is bonded to two Na, one Sr, and one Si atom to form a mixture of distorted corner and edge-sharing ONa2SrSi tetrahedra. In the twenty-second O site, O is bonded in a 3-coordinate geometry to one Na and two Si atoms. In the twenty-third O site, O is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na, one Sr, and one Si atom.