LaNi5H6 crystallizes in the trigonal P3m1 space group. La(1) is bonded to six equivalent H(1) and six equivalent H(2) atoms to form LaH12 cuboctahedra that share corners with six equivalent La(1)H12 cuboctahedra, corners with three equivalent Ni(2)H6 octahedra, faces with two equivalent La(1)H12 cuboctahedra, and faces with three equivalent Ni(2)H6 octahedra. The corner-sharing octahedral tilt angles are 12°. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a trigonal non-coplanar geometry to one H(1) and two equivalent H(2) atoms. In the second Ni site, Ni(2) is bonded to three equivalent H(1) and three equivalent H(2) atoms to form distorted NiH6 octahedra that share corners with three equivalent La(1)H12 cuboctahedra and faces with three equivalent La(1)H12 cuboctahedra. In the third Ni site, Ni(3) is bonded in a trigonal non-coplanar geometry to three equivalent H(1) atoms. There are two inequivalent H sites. In the first H site, H(1) is bonded to two equivalent La(1), one Ni(1), one Ni(2), and one Ni(3) atom to form a mixture of distorted corner and edge-sharing HLa2Ni3 trigonal bipyramids. In the second H site, H(2) is bonded in a 5-coordinate geometry to two equivalent La(1), one Ni(2), and two equivalent Ni(1) atoms.
LaNi5H6 crystallizes in the trigonal P3m1 space group. La(1) is bonded to six equivalent H(1) and six equivalent H(2) atoms to form LaH12 cuboctahedra that share corners with six equivalent La(1)H12 cuboctahedra, corners with three equivalent Ni(2)H6 octahedra, faces with two equivalent La(1)H12 cuboctahedra, and faces with three equivalent Ni(2)H6 octahedra. The corner-sharing octahedral tilt angles are 12°. All La(1)-H(1) bond lengths are 2.65 Å. There are three shorter (2.54 Å) and three longer (2.77 Å) La(1)-H(2) bond lengths. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a trigonal non-coplanar geometry to one H(1) and two equivalent H(2) atoms. The Ni(1)-H(1) bond length is 1.63 Å. Both Ni(1)-H(2) bond lengths are 1.64 Å. In the second Ni site, Ni(2) is bonded to three equivalent H(1) and three equivalent H(2) atoms to form distorted NiH6 octahedra that share corners with three equivalent La(1)H12 cuboctahedra and faces with three equivalent La(1)H12 cuboctahedra. All Ni(2)-H(1) bond lengths are 1.64 Å. All Ni(2)-H(2) bond lengths are 1.94 Å. In the third Ni site, Ni(3) is bonded in a trigonal non-coplanar geometry to three equivalent H(1) atoms. All Ni(3)-H(1) bond lengths are 1.66 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded to two equivalent La(1), one Ni(1), one Ni(2), and one Ni(3) atom to form a mixture of distorted corner and edge-sharing HLa2Ni3 trigonal bipyramids. In the second H site, H(2) is bonded in a 5-coordinate geometry to two equivalent La(1), one Ni(2), and two equivalent Ni(1) atoms.