DOI: 10.17188/1705870
title: Materials Data on ErFe2H3 by Materials Project

description: ErFe2H3 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent Er sites. In the first Er site, Er is bonded in a 6-coordinate geometry to three equivalent Fe and six H atoms. All Er–Fe bond lengths are 3.24 Å. There are three shorter (2.13 Å) and three longer (2.25 Å) Er–H bond lengths. In the second Er site, Er is bonded in a 6-coordinate geometry to three Fe and six H atoms. There are two shorter (3.24 Å) and one longer (3.28 Å) Er–Fe bond lengths. There are a spread of Er–H bond distances ranging from 2.11–2.20 Å. There are four inequivalent Fe sites. In the first Fe site, Fe is bonded in a square co-planar geometry to two Fe and four H atoms. There are one shorter (2.61 Å) and one longer (2.66 Å) Fe–Fe bond lengths. There is two shorter (1.65 Å) and two longer (1.67 Å) Fe–H bond length. In the second Fe site, Fe is bonded to six equivalent Er and six equivalent Fe atoms to form FeEr6Fe6 cuboctahedra that share corners with six equivalent FeEr6Fe6 cuboctahedra, corners with twelve HEr2Fe2 trigonal pyramids, edges with six equivalent FeEr6Fe6 cuboctahedra, edges with six equivalent HEr2Fe2 trigonal pyramids, and faces with twelve equivalent HEr2Fe2 tetrahedra. In the third Fe site, Fe is bonded to six Er and six Fe atoms to form FeEr6Fe6 cuboctahedra that share corners with six FeEr6Fe6 cuboctahedra, corners with eight equivalent HEr2Fe2 tetrahedra, corners with four HEr2Fe2 trigonal pyramids, edges with six FeEr6Fe6 cuboctahedra, edges with four equivalent HEr2Fe2 tetrahedra, edges with two equivalent HEr2Fe2 trigonal pyramids, faces with four equivalent HEr2Fe2 tetrahedra, and faces with eight HEr2Fe2 trigonal pyramids. All Fe–Fe bond lengths are 2.63 Å. In the fourth Fe site, Fe is bonded in a square co-planar geometry to two equivalent Fe and four H atoms. There is two shorter (1.66 Å) and two longer (1.67 Å) Fe–H bond length. There are three inequivalent H sites. In the first H site, H is bonded to two Er and two equivalent Fe atoms to form distorted HEr2Fe2 trigonal pyramids that share corners with two FeEr6Fe6 cuboctahedra, corners with eight equivalent HEr2Fe2 tetrahedra, corners with two equivalent HEr2Fe2 trigonal pyramids, an edgeedge with one FeEr6Fe6 cuboctahedra, edges with three HEr2Fe2 trigonal pyramids, and faces with two equivalent FeEr6Fe6 cuboctahedra. In the second H site, H is bonded to two Er and two equivalent Fe atoms to form distorted HEr2Fe2 trigonal pyramids that share corners with two FeEr6Fe6 cuboctahedra, corners with four equivalent HEr2Fe2 tetrahedra, corners with six HEr2Fe2 trigonal pyramids, an edgeedge with one FeEr6Fe6 cuboctahedra, edges with two equivalent HEr2Fe2 tetrahedra, an edgeedge with one HEr2Fe2 trigonal pyramid, and faces with two equivalent FeEr6Fe6 cuboctahedra. In the third H site, H is bonded to two equivalent Er and two Fe atoms to form distorted HEr2Fe2 tetrahedra that share corners with two equivalent FeEr6Fe6 cuboctahedra, corners with four equivalent HEr2Fe2 tetrahedra, corners with six HEr2Fe2 trigonal pyramids, an edgeedge with one FeEr6Fe6 cuboctahedra, edges with two equivalent HEr2Fe2 tetrahedra, an edgeedge with one HEr2Fe2 trigonal pyramid, and faces with two FeEr6Fe6 cuboctahedra.