Materials Data on RbMg6Al by Materials Project
RbMg6Al crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Rb is bonded to ten Mg and two equivalent Al atoms to form a mixture of face and corner-sharing RbMg10Al2 cuboctahedra. There are a spread of Rb–Mg bond distances ranging from 3.45–3.56 Å. Both Rb–Al bond lengths are 3.50 Å. There are four inequivalent Mg sites. In the first Mg site, Mg is bonded in a 3-coordinate geometry to two equivalent Rb, six Mg, and one Al atom. There are a spread of Mg–Mg bond distances ranging from 3.17–3.53 Å. The Mg–Al bond length is 2.93 Å. In the second Mg site, Mg is bonded in a 10-coordinate geometry to ten Mg atoms. There are two shorter (3.29 Å) and four longer (3.34 Å) Mg–Mg bond lengths. In the third Mg site, Mg is bonded in a 4-coordinate geometry to two equivalent Rb, six Mg, and two equivalent Al atoms. There are one shorter (3.29 Å) and one longer (3.41 Å) Mg–Mg bond lengths. Both Mg–Al bond lengths are 3.12 Å. In the fourth Mg site, Mg is bonded in a 12-coordinate geometry to two equivalent Rb and eight Mg atoms. Al is bonded in a 8-coordinate geometry to two equivalent Rb and six Mg atoms.