Materials Data on Mg4Sb2O9 by Materials Project
Mg4Sb2O9 is Ilmenite-like structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are four inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Mg–O bond distances ranging from 2.01–2.42 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with six MgO6 octahedra, edges with three SbO6 octahedra, and a faceface with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 44–64°. There are a spread of Mg–O bond distances ranging from 2.03–2.25 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with seven SbO6 octahedra, edges with three MgO6 octahedra, and a faceface with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 43–64°. There are a spread of Mg–O bond distances ranging from 2.05–2.23 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with four equivalent MgO6 octahedra, corners with five SbO6 octahedra, edges with two equivalent MgO6 octahedra, and a faceface with one SbO6 octahedra. The corner-sharing octahedra tilt angles range from 44–63°. There are a spread of Mg–O bond distances ranging from 2.04–2.22 Å. There are two inequivalent Sb5+ sites. In the first Sb5+ site, Sb5+ is bonded to six O2- atoms to form SbO6 octahedra that share corners with four MgO6 octahedra, an edgeedge with one MgO6 octahedra, and edges with two equivalent SbO6 octahedra. The corner-sharing octahedra tilt angles range from 46–63°. There are a spread of Sb–O bond distances ranging from 1.93–2.14 Å. In the second Sb5+ site, Sb5+ is bonded to six O2- atoms to form SbO6 octahedra that share corners with eight MgO6 octahedra, an edgeedge with one SbO6 octahedra, edges with two equivalent MgO6 octahedra, and a faceface with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 43–60°. There are a spread of Sb–O bond distances ranging from 1.97–2.15 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted see-saw-like geometry to three Mg2+ and one Sb5+ atom. In the second O2- site, O2- is bonded in a distorted see-saw-like geometry to three Mg2+ and one Sb5+ atom. In the third O2- site, O2- is bonded to three Mg2+ and one Sb5+ atom to form a mixture of distorted edge and corner-sharing OMg3Sb trigonal pyramids. In the fourth O2- site, O2- is bonded to two equivalent Mg2+ and two equivalent Sb5+ atoms to form distorted OMg2Sb2 trigonal pyramids that share corners with eight OMg3Sb trigonal pyramids and edges with three OMg2Sb2 trigonal pyramids. In the fifth O2- site, O2- is bonded to three Mg2+ and one Sb5+ atom to form distorted OMg3Sb trigonal pyramids that share corners with seven OMg3Sb trigonal pyramids and an edgeedge with one OMg2Sb2 trigonal pyramid. In the sixth O2- site, O2- is bonded in a distorted see-saw-like geometry to three Mg2+ and one Sb5+ atom. In the seventh O2- site, O2- is bonded to two Mg2+ and two equivalent Sb5+ atoms to form a mixture of distorted edge and corner-sharing OMg2Sb2 trigonal pyramids. In the eighth O2- site, O2- is bonded to two Mg2+ and two equivalent Sb5+ atoms to form a mixture of distorted edge and corner-sharing OMg2Sb2 trigonal pyramids. In the ninth O2- site, O2- is bonded in a distorted see-saw-like geometry to three Mg2+ and one Sb5+ atom.