Materials Data on RbMg6Nb by Materials Project

Abstract

RbMg6Nb crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Rb is bonded to twelve Mg atoms to form RbMg12 cuboctahedra that share corners with six equivalent RbMg12 cuboctahedra, faces with two equivalent RbMg12 cuboctahedra, and faces with six equivalent NbMg12 cuboctahedra. There are a spread of Rb–Mg bond distances ranging from 3.27–3.36 Å. There are four inequivalent Mg sites. In the first Mg site, Mg is bonded in a 4-coordinate geometry to two equivalent Rb, six Mg, and two equivalent Nb atoms. There are a spread of Mg–Mg bond distances ranging from 3.01–3.30 Å. Both Mg–Nb bond lengths are 3.10 Å. In the second Mg site, Mg is bonded in a 12-coordinate geometry to two equivalent Rb, six Mg, and two equivalent Nb atoms. All Mg–Mg bond lengths are 3.18 Å. Both Mg–Nb bond lengths are 3.13 Å. In the third Mg site, Mg is bonded in a 4-coordinate geometry to two equivalent Rb, seven Mg, and two equivalent Nb atoms. There are a spread of Mg–Mg bond distances ranging from 3.10–3.48 Å. There are one shorter (3.20 Å) and one longer (3.38 Å) Mg–Nb bond lengths. In the fourth Mg site, Mg is bonded in a 12-coordinate geometry to two equivalent Rb, eight Mg, and two equivalent Nb atoms. Both Mg–Nb bond lengths are 3.36 Å. Nb is bonded to twelve Mg atoms to form NbMg12 cuboctahedra that share corners with six equivalent NbMg12 cuboctahedra, faces with two equivalent NbMg12 cuboctahedra, and faces with six equivalent RbMg12 cuboctahedra.