Materials Data on MgB2O7 by Materials Project
MgB2O7 crystallizes in the tetragonal P4_2 space group. The structure is three-dimensional. Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six BO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.04–2.11 Å. There are two inequivalent B sites. In the first B site, B is bonded to four O atoms to form BO4 tetrahedra that share corners with three equivalent MgO6 octahedra and a cornercorner with one BO4 tetrahedra. The corner-sharing octahedra tilt angles range from 31–54°. There are a spread of B–O bond distances ranging from 1.42–1.51 Å. In the second B site, B is bonded to four O atoms to form BO4 tetrahedra that share corners with three equivalent MgO6 octahedra and a cornercorner with one BO4 tetrahedra. The corner-sharing octahedra tilt angles range from 32–53°. There are a spread of B–O bond distances ranging from 1.42–1.51 Å. There are eight inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to one Mg and one B atom. In the second O site, O is bonded in a bent 120 degrees geometry to one Mg and one B atom. In the third O site, O is bonded in a distorted bent 120 degrees geometry to two equivalent B atoms. In the fourth O site, O is bonded in a distorted bent 120 degrees geometry to two equivalent B atoms. In the fifth O site, O is bonded in a bent 150 degrees geometry to one Mg and one B atom. In the sixth O site, O is bonded in a bent 150 degrees geometry to one Mg and one B atom. In the seventh O site, O is bonded in a bent 120 degrees geometry to one Mg and one B atom. In the eighth O site, O is bonded in a distorted bent 120 degrees geometry to one Mg and one B atom.