DOE OSTI2020
LaNi5H6 crystallizes in the trigonal P3 space group. The structure is three-dimensional. La is bonded to twelve H atoms to form LaH12 cuboctahedra that share corners with six equivalent LaH12 cuboctahedra, corners with three equivalent NiH6 octahedra, faces with two equivalent LaH12 cuboctahedra, and faces with three equivalent NiH6 octahedra. The corner-sharing octahedral tilt angles are 12°. There are a spread of La–H bond distances ranging from 2.54–2.77 Å. There are three inequivalent Ni sites. In the first Ni site, Ni is bonded in a trigonal non-coplanar geometry to three H atoms. There are a spread of Ni–H bond distances ranging from 1.63–1.65 Å. In the second Ni site, Ni is bonded to six H atoms to form distorted NiH6 octahedra that share corners with three equivalent LaH12 cuboctahedra and faces with three equivalent LaH12 cuboctahedra. There is three shorter (1.64 Å) and three longer (1.94 Å) Ni–H bond length. In the third Ni site, Ni is bonded in a trigonal non-coplanar geometry to three equivalent H atoms. All Ni–H bond lengths are 1.66 Å. There are two inequivalent H sites. In the first H site, H is bonded to two equivalent La and three Ni atoms to form a mixture of distorted corner and edge-sharing HLa2Ni3 trigonal bipyramids. In the second H site, H is bonded in a 5-coordinate geometry to two equivalent La and three Ni atoms.