Materials Data on Mg3Sb2O7 by Materials Project
Mg3Sb2O7 is Hausmannite-derived structured and crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 trigonal pyramids that share corners with eight equivalent SbO6 octahedra and corners with two equivalent MgO4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 66–82°. There are a spread of Mg–O bond distances ranging from 2.04–2.06 Å. In the second 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 2.04–2.73 Å. Sb4+ is bonded to six O2- atoms to form SbO6 octahedra that share corners with five equivalent SbO6 octahedra and corners with four equivalent MgO4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 44–63°. There are a spread of Sb–O bond distances ranging from 2.06–2.32 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to three equivalent Mg2+ and one Sb4+ atom to form distorted OMg3Sb tetrahedra that share corners with seven OMg3Sb tetrahedra and edges with two equivalent OMg2Sb2 tetrahedra. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Mg2+ and two equivalent Sb4+ atoms. In the third O2- site, O2- is bonded to two Mg2+ and two equivalent Sb4+ atoms to form distorted OMg2Sb2 tetrahedra that share corners with four OMg2Sb2 tetrahedra and edges with two equivalent OMg3Sb tetrahedra. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Mg2+ and two equivalent Sb4+ atoms.