Materials Data on Mg5Nb(BO4)3 by Materials Project
Mg5NbO3(BO3)3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are three inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 55–68°. There are a spread of Mg–O bond distances ranging from 2.06–2.19 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 55–66°. There are a spread of Mg–O bond distances ranging from 2.03–2.22 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 68°. There are a spread of Mg–O bond distances ranging from 2.06–2.19 Å. Nb5+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Nb–O bond distances ranging from 1.91–2.45 Å. There are two inequivalent B3+ sites. In the first B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.36–1.42 Å. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.37–1.42 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+, one Nb5+, and one B3+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Mg2+, one Nb5+, and one B3+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to three Mg2+ and one B3+ atom. In the fourth O2- site, O2- is bonded to three Mg2+ and one Nb5+ atom to form distorted OMg3Nb tetrahedra that share corners with three OMg2NbB tetrahedra and edges with two equivalent OMg3Nb tetrahedra. In the fifth O2- site, O2- is bonded to two equivalent Mg2+, one Nb5+, and one B3+ atom to form distorted corner-sharing OMg2NbB tetrahedra. In the sixth O2- site, O2- is bonded to three Mg2+ and one Nb5+ atom to form a mixture of edge and corner-sharing OMg3Nb tetrahedra. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mg2+ and one B3+ atom. In the eighth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Mg2+ and one B3+ atom.