DOI: 10.17188/1727004
title: Materials Data on Nb19Fe20 by Materials Project

description: Nb19Fe20 is Frank-Kasper $\mu$ Phase-like structured and crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. there are ten inequivalent Nb sites. In the first Nb site, Nb is bonded in a 8-coordinate geometry to eight Nb and six equivalent Fe atoms. There are a spread of Nb–Nb bond distances ranging from 2.65–3.13 Å. All Nb–Fe bond lengths are 2.71 Å. In the second Nb site, Nb is bonded in a 8-coordinate geometry to eight Nb and six equivalent Fe atoms. There are a spread of Nb–Nb bond distances ranging from 2.65–3.14 Å. All Nb–Fe bond lengths are 2.71 Å. In the third Nb site, Nb is bonded in a 8-coordinate geometry to eight Nb and six equivalent Fe atoms. There are one shorter (2.77 Å) and six longer (3.15 Å) Nb–Nb bond lengths. All Nb–Fe bond lengths are 2.69 Å. In the fourth Nb site, Nb is bonded in a 6-coordinate geometry to nine Nb and six Fe atoms. All Nb–Nb bond lengths are 2.85 Å. There are three shorter (2.78 Å) and three longer (2.81 Å) Nb–Fe bond lengths. In the fifth Nb site, Nb is bonded in a 9-coordinate geometry to nine Nb and six equivalent Fe atoms. All Nb–Nb bond lengths are 2.85 Å. All Nb–Fe bond lengths are 2.84 Å. In the sixth Nb site, Nb is bonded in a 6-coordinate geometry to nine Nb and six Fe atoms. There are three shorter (2.81 Å) and three longer (2.82 Å) Nb–Fe bond lengths. In the seventh Nb site, Nb is bonded in a 6-coordinate geometry to four Nb and twelve Fe atoms. All Nb–Nb bond lengths are 2.94 Å. There are a spread of Nb–Fe bond distances ranging from 2.79–2.96 Å. In the eighth Nb site, Nb is bonded in a 6-coordinate geometry to four Nb and twelve Fe atoms. There are a spread of Nb–Fe bond distances ranging from 2.78–2.97 Å. In the ninth Nb site, Nb is bonded in a 10-coordinate geometry to seven Nb and nine equivalent Fe atoms. There are three shorter (2.88 Å) and three longer (2.97 Å) Nb–Nb bond lengths. There are three shorter (2.91 Å) and six longer (3.00 Å) Nb–Fe bond lengths. In the tenth Nb site, Nb is bonded to six equivalent Nb and six equivalent Fe atoms to form distorted NbNb6Fe6 cuboctahedra that share corners with twelve equivalent FeNb8Fe4 cuboctahedra, edges with six equivalent NbNb6Fe6 cuboctahedra, and faces with eighteen equivalent FeNb8Fe4 cuboctahedra. All Nb–Fe bond lengths are 2.58 Å. There are four inequivalent Fe sites. In the first Fe site, Fe is bonded to six Nb and six Fe atoms to form FeNb6Fe6 cuboctahedra that share corners with twelve FeNb7Fe5 cuboctahedra, edges with six equivalent FeNb6Fe6 cuboctahedra, and faces with eighteen FeNb7Fe5 cuboctahedra. All Fe–Fe bond lengths are 2.47 Å. In the second Fe site, Fe is bonded to eight Nb and four equivalent Fe atoms to form distorted FeNb8Fe4 cuboctahedra that share corners with two equivalent NbNb6Fe6 cuboctahedra, corners with thirteen FeNb8Fe4 cuboctahedra, edges with five FeNb8Fe4 cuboctahedra, faces with three equivalent NbNb6Fe6 cuboctahedra, and faces with ten equivalent FeNb8Fe4 cuboctahedra. There are two shorter (2.41 Å) and two longer (2.52 Å) Fe–Fe bond lengths. In the third Fe site, Fe is bonded to seven Nb and five Fe atoms to form FeNb7Fe5 cuboctahedra that share corners with fifteen FeNb6Fe6 cuboctahedra, edges with five FeNb7Fe5 cuboctahedra, and faces with thirteen FeNb6Fe6 cuboctahedra. There are two shorter (2.46 Å) and two longer (2.47 Å) Fe–Fe bond lengths. In the fourth Fe site, Fe is bonded to seven Nb and five Fe atoms to form FeNb7Fe5 cuboctahedra that share corners with fifteen FeNb6Fe6 cuboctahedra, edges with five FeNb8Fe4 cuboctahedra, and faces with thirteen FeNb6Fe6 cuboctahedra. There are two shorter (2.46 Å) and two longer (2.47 Å) Fe–Fe bond lengths.