DOI: 10.17188/1723312
title: Materials Data on Mg10Si3(O7F2)2 by Materials Project

description: Mg10Si3(O7F2)2 crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. there are four inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- and two equivalent F1- atoms to form MgO4F2 octahedra that share a cornercorner with one SiO6 octahedra, corners with four MgO6 octahedra, a cornercorner with one SiO4 tetrahedra, an edgeedge with one SiO6 octahedra, and edges with six MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–52°. There are a spread of Mg–O bond distances ranging from 2.05–2.23 Å. Both Mg–F bond lengths are 1.97 Å. In the second Mg2+ site, Mg2+ is bonded to four O2- and two equivalent F1- atoms to form MgO4F2 octahedra that share corners with five MgO4F2 octahedra, corners with two equivalent SiO4 tetrahedra, an edgeedge with one SiO6 octahedra, and edges with five MgO4F2 octahedra. The corner-sharing octahedra tilt angles range from 7–53°. There are a spread of Mg–O bond distances ranging from 2.07–2.21 Å. There is one shorter (1.96 Å) and one longer (1.98 Å) Mg–F bond length. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with four equivalent MgO4F2 octahedra, corners with two equivalent SiO4 tetrahedra, edges with two equivalent SiO6 octahedra, and edges with seven MgO4F2 octahedra. The corner-sharing octahedra tilt angles range from 7–22°. There are a spread of Mg–O bond distances ranging from 2.07–2.19 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent MgO4F2 octahedra, corners with four equivalent SiO4 tetrahedra, an edgeedge with one SiO6 octahedra, and edges with five MgO6 octahedra. The corner-sharing octahedral tilt angles are 17°. There are a spread of Mg–O bond distances ranging from 2.06–2.17 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to six O2- atoms to form SiO6 octahedra that share corners with two equivalent MgO4F2 octahedra and edges with twelve MgO4F2 octahedra. The corner-sharing octahedral tilt angles are 1°. There is four shorter (1.80 Å) and two longer (1.94 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 eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 46–59°. There is one shorter (1.63 Å) and three longer (1.68 Å) Si–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Mg2+ and one Si4+ atom. In the third O2- site, O2- is bonded to four Mg2+ and one Si4+ atom to form distorted OMg4Si square pyramids that share corners with two equivalent OMg4Si square pyramids, edges with three equivalent OMg5Si octahedra, and edges with two equivalent OMg4Si square pyramids. In the fourth O2- site, O2- is bonded to five Mg2+ and one Si4+ atom to form OMg5Si octahedra that share a cornercorner with one OMg5Si octahedra, an edgeedge with one OMg5Si octahedra, and edges with six equivalent OMg4Si square pyramids. The corner-sharing octahedral tilt angles are 0°. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. F1- is bonded in a distorted trigonal planar geometry to three Mg2+ atoms.