DOI: 10.17188/1696134
title: Materials Data on Nd2Fe15(SiH)2 by Materials Project

description: Nd2Fe15(SiH)2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Nd is bonded in a distorted bent 120 degrees geometry to eight Fe, one Si, and two equivalent H atoms. There are a spread of Nd–Fe bond distances ranging from 3.05–3.35 Å. The Nd–Si bond length is 3.09 Å. Both Nd–H bond lengths are 2.46 Å. There are six inequivalent Fe sites. In the first Fe site, Fe is bonded to two equivalent Nd, eight Fe, and two equivalent Si atoms to form distorted FeNd2Fe8Si2 cuboctahedra that share corners with eight FeNd2Fe8Si2 cuboctahedra, corners with four equivalent HNd2Fe4 octahedra, edges with three FeNd2Fe8Si2 cuboctahedra, edges with two equivalent HNd2Fe4 octahedra, and faces with nine FeNd2Fe8Si2 cuboctahedra. The corner-sharing octahedra tilt angles range from 24–29°. There are a spread of Fe–Fe bond distances ranging from 2.40–2.70 Å. Both Fe–Si bond lengths are 2.74 Å. In the second Fe site, Fe is bonded in a single-bond geometry to four Fe, two equivalent Si, and one H atom. There are two shorter (2.44 Å) and one longer (2.52 Å) Fe–Fe bond lengths. There are one shorter (2.70 Å) and one longer (2.71 Å) Fe–Si bond lengths. The Fe–H bond length is 1.86 Å. In the third Fe site, Fe is bonded to two equivalent Nd, eight Fe, and two equivalent Si atoms to form distorted FeNd2Fe8Si2 cuboctahedra that share corners with fourteen FeNd2Fe8Si2 cuboctahedra, edges with two equivalent FeNd3Fe8Si cuboctahedra, faces with ten FeNd2Fe8Si2 cuboctahedra, and faces with four equivalent HNd2Fe4 octahedra. All Fe–Fe bond lengths are 2.43 Å. Both Fe–Si bond lengths are 2.58 Å. In the fourth Fe site, Fe is bonded to two equivalent Nd, eight Fe, and two equivalent Si atoms to form distorted FeNd2Fe8Si2 cuboctahedra that share corners with eight FeNd2Fe8Si2 cuboctahedra, corners with two equivalent HNd2Fe4 octahedra, edges with four FeNd3Fe8Si cuboctahedra, faces with eight FeNd2Fe8Si2 cuboctahedra, and faces with two equivalent HNd2Fe4 octahedra. The corner-sharing octahedral tilt angles are 47°. All Fe–Fe bond lengths are 2.43 Å. Both Fe–Si bond lengths are 2.58 Å. In the fifth Fe site, Fe is bonded to three equivalent Nd, eight Fe, and one Si atom to form FeNd3Fe8Si cuboctahedra that share corners with eleven FeNd2Fe8Si2 cuboctahedra, corners with four equivalent HNd2Fe4 octahedra, edges with four FeNd2Fe8Si2 cuboctahedra, faces with eight FeNd2Fe8Si2 cuboctahedra, and faces with two equivalent HNd2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 63–71°. Both Fe–Fe bond lengths are 2.50 Å. The Fe–Si bond length is 2.58 Å. In the sixth Fe site, Fe is bonded in a single-bond geometry to four Fe, one Si, and one H atom. The Fe–Si bond length is 2.58 Å. The Fe–H bond length is 1.98 Å. Si is bonded in a 7-coordinate geometry to one Nd, twelve Fe, and one Si atom. The Si–Si bond length is 2.55 Å. H is bonded to two equivalent Nd and four Fe atoms to form HNd2Fe4 octahedra that share corners with ten FeNd2Fe8Si2 cuboctahedra, corners with two equivalent HNd2Fe4 octahedra, edges with two equivalent FeNd2Fe8Si2 cuboctahedra, and faces with six FeNd2Fe8Si2 cuboctahedra. The corner-sharing octahedral tilt angles are 61°.