Materials Data on Rb3MgH5 by Materials Project
Rb3MgH5 crystallizes in the tetragonal P4/ncc space group. The structure is three-dimensional. there are two inequivalent Rb1+ sites. In the first Rb1+ site, Rb1+ is bonded in a 6-coordinate geometry to six H1- atoms. There are a spread of Rb–H bond distances ranging from 2.97–3.20 Å. In the second Rb1+ site, Rb1+ is bonded to six H1- atoms to form distorted RbH6 pentagonal pyramids that share corners with two equivalent RbH6 pentagonal pyramids, corners with four equivalent MgH4 tetrahedra, and edges with four equivalent RbH6 pentagonal pyramids. There are a spread of Rb–H bond distances ranging from 2.90–3.04 Å. Mg2+ is bonded to four equivalent H1- atoms to form MgH4 tetrahedra that share corners with eight equivalent RbH6 pentagonal pyramids. All Mg–H bond lengths are 1.86 Å. There are two inequivalent H1- sites. In the first H1- site, H1- is bonded to six Rb1+ atoms to form distorted corner-sharing HRb6 octahedra. The corner-sharing octahedra tilt angles range from 0–28°. In the second H1- site, H1- is bonded in a distorted rectangular see-saw-like geometry to three Rb1+ and one Mg2+ atom.