Materials Data on Ca2Mg2B4O13 by Materials Project
Ca2Mg2B4O13 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. Ca is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Ca–O bond distances ranging from 2.35–2.52 Å. There are three inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 14°. There are a spread of Mg–O bond distances ranging from 2.08–2.19 Å. In the second Mg site, Mg is bonded in a distorted hexagonal planar geometry to six O atoms. There are four shorter (2.03 Å) and two longer (2.10 Å) Mg–O bond lengths. In the third Mg site, Mg is bonded to six O atoms to form edge-sharing MgO6 octahedra. There are four shorter (2.11 Å) and two longer (2.37 Å) Mg–O bond lengths. There are three inequivalent B sites. In the first B site, B is bonded to four O atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.44–1.50 Å. In the second B site, B is bonded to four O atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.45–1.49 Å. In the third B site, B is bonded in a trigonal planar geometry to three O atoms. There are a spread of B–O bond distances ranging from 1.37–1.39 Å. There are nine inequivalent O sites. In the first O site, O is bonded in a 4-coordinate geometry to one Ca, two Mg, and one B atom. In the second O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the third O site, O is bonded in a distorted bent 120 degrees geometry to one Ca and two B atoms. In the fourth O site, O is bonded in a distorted single-bond geometry to two equivalent Ca and one B atom. In the fifth O site, O is bonded in a distorted bent 120 degrees geometry to one Ca and two B atoms. In the sixth O site, O is bonded in a distorted see-saw-like geometry to two equivalent Ca and two Mg atoms. In the seventh O site, O is bonded in a see-saw-like geometry to two equivalent Ca and two equivalent Mg atoms. In the eighth O site, O is bonded in a distorted single-bond geometry to two equivalent Ca and one B atom. In the ninth O site, O is bonded in a trigonal non-coplanar geometry to one Ca and two Mg atoms.