Materials Data on MgSi2WO6 by Materials Project
MgWSi2O6 is Esseneite structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with eight equivalent SiO4 tetrahedra and edges with three equivalent WO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.03–2.32 Å. W2+ is bonded to six O2- atoms to form WO6 octahedra that share corners with six equivalent SiO4 tetrahedra, edges with two equivalent WO6 octahedra, and edges with three equivalent MgO6 octahedra. There are four shorter (2.24 Å) and two longer (2.28 Å) W–O bond lengths. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent WO6 octahedra, corners with four equivalent MgO6 octahedra, and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–61°. There are a spread of Si–O bond distances ranging from 1.60–1.70 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal planar geometry to one Mg2+ and two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Mg2+, one W2+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to one Mg2+, two equivalent W2+, and one Si4+ atom.