Materials Data on MgB7 by Materials Project
MgB7 is Magnesium tetraboride-like structured and crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. there are two inequivalent Mg sites. In the first Mg site, Mg is bonded in a 12-coordinate geometry to twelve B atoms. There are a spread of Mg–B bond distances ranging from 2.18–2.45 Å. In the second Mg site, Mg is bonded in a 6-coordinate geometry to fourteen B atoms. There are a spread of Mg–B bond distances ranging from 2.34–2.85 Å. There are five inequivalent B sites. In the first B site, B is bonded in a 6-coordinate geometry to three Mg and three B atoms. There is two shorter (1.75 Å) and one longer (1.80 Å) B–B bond length. In the second B site, B is bonded in a 8-coordinate geometry to two Mg and six B atoms. There are a spread of B–B bond distances ranging from 1.78–1.85 Å. In the third B site, B is bonded in a 8-coordinate geometry to two equivalent Mg and six B atoms. There is two shorter (1.79 Å) and one longer (1.85 Å) B–B bond length. In the fourth B site, B is bonded in a 6-coordinate geometry to six B atoms. There is one shorter (1.76 Å) and two longer (1.81 Å) B–B bond length. In the fifth B site, B is bonded in a 8-coordinate geometry to two equivalent Mg and six B atoms. There is one shorter (1.81 Å) and one longer (1.86 Å) B–B bond length.