Materials Data on LaNi5H7 by Materials Project

Abstract

LaNi5H7 crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. La2+ is bonded to twelve H1- atoms to form LaH12 cuboctahedra that share corners with six equivalent LaH12 cuboctahedra, corners with six equivalent NiH4 tetrahedra, edges with nine NiH4 tetrahedra, and faces with two equivalent LaH12 cuboctahedra. There are a spread of La–H bond distances ranging from 2.55–2.69 Å. There are three inequivalent Ni1+ sites. In the first Ni1+ site, Ni1+ is bonded to four H1- atoms to form NiH4 tetrahedra that share corners with two equivalent LaH12 cuboctahedra, corners with six NiH4 tetrahedra, and edges with two equivalent LaH12 cuboctahedra. There are a spread of Ni–H bond distances ranging from 1.62–1.66 Å. In the second Ni1+ site, Ni1+ is bonded to four H1- atoms to form NiH4 tetrahedra that share corners with six equivalent NiH4 tetrahedra and edges with three equivalent LaH12 cuboctahedra. There is one shorter (1.61 Å) and three longer (1.66 Å) Ni–H bond length. In the third Ni1+ site, Ni1+ is bonded in a trigonal non-coplanar geometry to three equivalent H1- atoms. All Ni–H bond lengths are 1.63 Å. There are three inequivalent H1- sites. In the first H1- site, H1- is bonded in a 5-coordinate geometry to two equivalent La2+ and three Ni1+ atoms. In the second H1- site, H1- is bonded in a tetrahedral geometry to four Ni1+ atoms. In the third H1- site, H1- is bonded in a 2-coordinate geometry to two equivalent La2+ and two equivalent Ni1+ atoms.