Materials Data on LaFe5H7 by Materials Project

Abstract

LaFe5H7 crystallizes in the orthorhombic Cccm space group. The structure is three-dimensional. La is bonded in a 10-coordinate geometry to ten H atoms. There are a spread of La–H bond distances ranging from 2.38–2.77 Å. There are three inequivalent Fe sites. In the first Fe site, Fe is bonded to four equivalent H atoms to form distorted corner-sharing FeH4 tetrahedra. All Fe–H bond lengths are 1.71 Å. In the second Fe site, Fe is bonded to five H atoms to form distorted FeH5 trigonal bipyramids that share corners with two equivalent FeH4 tetrahedra and corners with three equivalent FeH5 trigonal bipyramids. There are a spread of Fe–H bond distances ranging from 1.70–1.92 Å. In the third Fe site, Fe is bonded in a distorted T-shaped geometry to three H atoms. There is two shorter (1.73 Å) and one longer (1.76 Å) Fe–H bond length. There are three inequivalent H sites. In the first H site, H is bonded to two equivalent La and four Fe atoms to form distorted HLa2Fe4 octahedra that share corners with two equivalent HLa2Fe4 octahedra, corners with twenty HLa2Fe2 tetrahedra, and edges with four equivalent HLa2Fe2 tetrahedra. The corner-sharing octahedral tilt angles are 0°. In the second H site, H is bonded to two equivalent La and two equivalent Fe atoms to form distorted HLa2Fe2 tetrahedra that share corners with two equivalent HLa2Fe4 octahedra, corners with fourteen HLa2Fe2 tetrahedra, edges with two equivalent HLa2Fe4 octahedra, and edges with three HLa2Fe2 tetrahedra. The corner-sharing octahedral tilt angles are 60°. In the third H site, H is bonded to one La and three Fe atoms to form distorted HLaFe3 tetrahedra that share corners with four equivalent HLa2Fe4 octahedra, corners with ten HLa2Fe2 tetrahedra, and edges with two HLa2Fe2 tetrahedra. The corner-sharing octahedra tilt angles range from 47–92°.