Materials Data on RbMg6BO7 by Materials Project

Abstract

RbMg6BO7 crystallizes in the tetragonal P4mm space group. The structure is two-dimensional and consists of one RbMg6BO7 sheet oriented in the (0, 0, 1) direction. Rb is bonded in a 4-coordinate geometry to four equivalent O atoms. All Rb–O bond lengths are 2.68 Å. There are four inequivalent Mg sites. In the first Mg site, Mg is bonded to five O atoms to form a mixture of distorted edge and corner-sharing MgO5 square pyramids. There are one shorter (2.03 Å) and four longer (2.07 Å) Mg–O bond lengths. In the second Mg site, Mg is bonded to five O atoms to form a mixture of edge and corner-sharing MgO5 square pyramids. There are four shorter (2.02 Å) and one longer (2.11 Å) Mg–O bond lengths. In the third Mg site, Mg is bonded in a T-shaped geometry to three O atoms. There are two shorter (2.02 Å) and one longer (2.23 Å) Mg–O bond lengths. In the fourth Mg site, Mg is bonded to five O atoms to form MgO5 trigonal bipyramids that share corners with two equivalent MgO5 square pyramids, corners with four equivalent MgO5 trigonal bipyramids, edges with two equivalent BO5 square pyramids, and edges with four equivalent MgO5 trigonal bipyramids. There are a spread of Mg–O bond distances ranging from 1.95–2.13 Å. B is bonded to five O atoms to form distorted BO5 square pyramids that share corners with four equivalent BO5 square pyramids and edges with four equivalent MgO5 trigonal bipyramids. There is one shorter (1.44 Å) and four longer (2.04 Å) B–O bond length. There are five inequivalent O sites. In the first O site, O is bonded to five Mg atoms to form distorted OMg5 trigonal bipyramids that share corners with twelve OMg5 trigonal bipyramids and edges with four equivalent OMg4B square pyramids. In the second O site, O is bonded to five Mg atoms to form a mixture of edge and corner-sharing OMg5 square pyramids. In the third O site, O is bonded to four equivalent Mg and one B atom to form OMg4B square pyramids that share corners with four equivalent OMg4B square pyramids and edges with eight OMg5 trigonal bipyramids. In the fourth O site, O is bonded to two equivalent Rb, one Mg, and two equivalent B atoms to form distorted ORb2MgB2 trigonal bipyramids that share corners with six OMg5 trigonal bipyramids, edges with two equivalent OMg4B square pyramids, and edges with four equivalent ORb2MgB2 trigonal bipyramids. In the fifth O site, O is bonded to five Mg atoms to form a mixture of edge and corner-sharing OMg5 trigonal bipyramids.