Materials Data on RbMgH3 by Materials Project

Abstract

RbMgH3 is (Cubic) Perovskite-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Rb1+ sites. In the first Rb1+ site, Rb1+ is bonded to twelve H1- atoms to form RbH12 cuboctahedra that share corners with twelve RbH12 cuboctahedra, faces with six equivalent RbH12 cuboctahedra, and faces with eight MgH6 octahedra. There are six shorter (2.97 Å) and six longer (2.98 Å) Rb–H bond lengths. In the second Rb1+ site, Rb1+ is bonded to twelve H1- atoms to form RbH12 cuboctahedra that share corners with nine RbH12 cuboctahedra, corners with three equivalent MgH6 octahedra, faces with seven RbH12 cuboctahedra, and faces with seven MgH6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are a spread of Rb–H bond distances ranging from 2.96–3.05 Å. There are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six H1- atoms to form MgH6 octahedra that share corners with three equivalent RbH12 cuboctahedra, corners with three equivalent MgH6 octahedra, faces with seven RbH12 cuboctahedra, and a faceface with one MgH6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are three shorter (2.01 Å) and three longer (2.02 Å) Mg–H bond lengths. In the second Mg2+ site, Mg2+ is bonded to six equivalent H1- atoms to form MgH6 octahedra that share corners with six equivalent MgH6 octahedra and faces with eight RbH12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. All Mg–H bond lengths are 2.05 Å. There are two inequivalent H1- sites. In the first H1- site, H1- is bonded in a distorted L-shaped geometry to four Rb1+ and two equivalent Mg2+ atoms. In the second H1- site, H1- is bonded in a distorted linear geometry to four Rb1+ and two Mg2+ atoms.