DOI: 10.17188/1740466
title: Materials Data on Ba2Sr3CaMg2(SiO4)4 by Materials Project

description: Ba2Sr3CaMg2(SiO4)4 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share edges with six BaO12 cuboctahedra, edges with six SiO4 tetrahedra, and faces with two equivalent MgO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.83–3.21 Å. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share edges with six BaO12 cuboctahedra, edges with six SiO4 tetrahedra, and faces with two equivalent MgO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.81–3.20 Å. There are three inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 1-coordinate geometry to ten O2- atoms. There are a spread of Sr–O bond distances ranging from 2.38–2.83 Å. In the second Sr2+ site, Sr2+ is bonded in a 1-coordinate geometry to ten O2- atoms. There are a spread of Sr–O bond distances ranging from 2.39–2.83 Å. In the third Sr2+ site, Sr2+ is bonded in a 1-coordinate geometry to ten O2- atoms. There are a spread of Sr–O bond distances ranging from 2.38–2.84 Å. Ca2+ is bonded in a 1-coordinate geometry to ten O2- atoms. There are a spread of Ca–O bond distances ranging from 2.30–2.88 Å. There are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra and faces with two equivalent BaO12 cuboctahedra. There are a spread of Mg–O bond distances ranging from 2.09–2.11 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra and faces with two equivalent BaO12 cuboctahedra. There are a spread of Mg–O bond distances ranging from 2.07–2.10 Å. There are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and edges with three BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 13°. There is one shorter (1.63 Å) and three longer (1.66 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and edges with three BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 13°. There is one shorter (1.61 Å) and three longer (1.66 Å) Si–O bond length. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and edges with three BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 13°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and edges with three BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 13°. There is one shorter (1.61 Å) and three longer (1.66 Å) Si–O bond length. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+, two Sr2+, one Ca2+, one Mg2+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+, three Sr2+, one Mg2+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+, two equivalent Sr2+, one Ca2+, one Mg2+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+, three Sr2+, one Mg2+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+, two Sr2+, one Ca2+, one Mg2+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+, two Sr2+, one Ca2+, one Mg2+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+, one Sr2+, two equivalent Ca2+, one Mg2+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+, three Sr2+, one Mg2+, and one Si4+ atom. In the ninth O2- site, O2- is bonded in a distorted linear geometry to three Ba2+, one Ca2+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a distorted linear geometry to three Ba2+, one Sr2+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a distorted linear geometry to three Ba2+, one Sr2+, and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a distorted linear geometry to three Ba2+, one Sr2+, and one Si4+ atom.