DOI: 10.17188/1689646
title: Materials Data on Mg7Fe(SiO4)4 by Materials Project

description: Mg7Fe(SiO4)4 is Spinel-derived structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are five inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with four equivalent MgO6 octahedra, corners with two equivalent SiO4 tetrahedra, edges with four MgO6 octahedra, and edges with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–63°. There are a spread of Mg–O bond distances ranging from 2.10–2.15 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with six MgO6 octahedra, corners with four SiO4 tetrahedra, edges with two MgO6 octahedra, and an edgeedge with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–64°. There are a spread of Mg–O bond distances ranging from 2.07–2.27 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with four equivalent MgO6 octahedra, corners with two equivalent SiO4 tetrahedra, edges with four MgO6 octahedra, and edges with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–63°. There are a spread of Mg–O bond distances ranging from 2.09–2.16 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with four equivalent MgO6 octahedra, corners with two equivalent SiO4 tetrahedra, edges with two equivalent MgO6 octahedra, edges with two equivalent FeO6 octahedra, and edges with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–62°. There are a spread of Mg–O bond distances ranging from 2.10–2.14 Å. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with eight MgO6 octahedra, corners with four SiO4 tetrahedra, an edgeedge with one MgO6 octahedra, an edgeedge with one FeO6 octahedra, and an edgeedge with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–63°. There are a spread of Mg–O bond distances ranging from 2.08–2.26 Å. Fe2+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four equivalent MgO6 octahedra, corners with two equivalent SiO4 tetrahedra, edges with four MgO6 octahedra, and edges with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–64°. There are a spread of Fe–O bond distances ranging from 2.14–2.21 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one FeO6 octahedra, corners with five MgO6 octahedra, an edgeedge with one FeO6 octahedra, and edges with two MgO6 octahedra. The corner-sharing octahedra tilt angles range from 53–61°. There are a spread of Si–O bond distances ranging from 1.64–1.67 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with six MgO6 octahedra and edges with three MgO6 octahedra. The corner-sharing octahedra tilt angles range from 56–61°. There are a spread of Si–O bond distances ranging from 1.64–1.68 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to three Mg2+ and one Si4+ atom to form distorted corner-sharing OMg3Si trigonal pyramids. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+, one Fe2+, and one Si4+ atom. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the fifth O2- site, O2- is bonded to two Mg2+, one Fe2+, and one Si4+ atom to form distorted corner-sharing OMg2FeSi trigonal pyramids. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+, one Fe2+, and one Si4+ atom.