Materials Data on NdMgNi4H7 by Materials Project

Abstract

MgNdNi4H7 crystallizes in the cubic F-43m space group. The structure is three-dimensional. Mg is bonded to six equivalent H atoms to form MgH6 octahedra that share corners with twelve equivalent NiH4 tetrahedra and faces with four equivalent NdH12 cuboctahedra. All Mg–H bond lengths are 1.98 Å. Nd is bonded to twelve equivalent H atoms to form NdH12 cuboctahedra that share corners with twelve equivalent NdH12 cuboctahedra, edges with twelve equivalent NiH4 tetrahedra, and faces with four equivalent MgH6 octahedra. All Nd–H bond lengths are 2.71 Å. Ni is bonded to four H atoms to form NiH4 tetrahedra that share corners with three equivalent MgH6 octahedra, corners with six equivalent NiH4 tetrahedra, and edges with three equivalent NdH12 cuboctahedra. The corner-sharing octahedral tilt angles are 57°. There is three shorter (1.63 Å) and one longer (1.64 Å) Ni–H bond length. There are two inequivalent H sites. In the first H site, H is bonded in a distorted trigonal planar geometry to one Mg, two equivalent Nd, and two equivalent Ni atoms. In the second H site, H is bonded in a tetrahedral geometry to four equivalent Ni atoms.