Materials Data on Mg2NiH4 by Materials Project

Mg2NiH4 crystallizes in the orthorhombic Imm2 space group. The structure is three-dimensional. Mg is bonded in a 7-coordinate geometry to seven H atoms. There are a spread of Mg–H bond distances ranging from 2.02–2.29 Å. Ni is bonded in a distorted trigonal pyramidal geometry to four H atoms. There is two shorter (1.53 Å) and two longer (1.55 Å) Ni–H bond length. There are two inequivalent H sites. In the first H site, H is bonded in a distorted see-saw-like geometry to three equivalent Mg and one Ni atom. In the second H site, H is bonded to four equivalent Mg and one Ni atom to form a mixture of distorted corner, edge, and face-sharing HMg4Ni square pyramids.