DOI: 10.17188/1709479
title: Materials Data on NbAlCr by Materials Project

description: AlNbCr is Frank-Kasper $\mu$ Phase-derived structured and crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are six inequivalent Nb sites. In the first Nb site, Nb is bonded in a 12-coordinate geometry to four Nb, five Cr, and seven Al atoms. There are a spread of Nb–Nb bond distances ranging from 3.05–3.20 Å. There are a spread of Nb–Cr bond distances ranging from 2.91–2.97 Å. There are a spread of Nb–Al bond distances ranging from 2.90–2.98 Å. In the second Nb site, Nb is bonded in a 12-coordinate geometry to four Nb, seven Cr, and five Al atoms. There are one shorter (3.03 Å) and two longer (3.07 Å) Nb–Nb bond lengths. There are a spread of Nb–Cr bond distances ranging from 2.88–3.02 Å. There are a spread of Nb–Al bond distances ranging from 2.86–3.01 Å. In the third Nb site, Nb is bonded in a 12-coordinate geometry to four Nb, seven Cr, and five Al atoms. There are one shorter (3.05 Å) and two longer (3.07 Å) Nb–Nb bond lengths. There are a spread of Nb–Cr bond distances ranging from 2.88–3.02 Å. There are a spread of Nb–Al bond distances ranging from 2.86–3.01 Å. In the fourth Nb site, Nb is bonded in a 12-coordinate geometry to four Nb, five Cr, and seven Al atoms. There are a spread of Nb–Cr bond distances ranging from 2.91–2.97 Å. There are a spread of Nb–Al bond distances ranging from 2.90–2.98 Å. In the fifth Nb site, Nb is bonded in a 12-coordinate geometry to four Nb, five Cr, and seven Al atoms. The Nb–Nb bond length is 3.20 Å. There are a spread of Nb–Cr bond distances ranging from 2.91–2.97 Å. There are a spread of Nb–Al bond distances ranging from 2.90–2.98 Å. In the sixth Nb site, Nb is bonded in a 12-coordinate geometry to four Nb, five Cr, and seven Al atoms. There are a spread of Nb–Cr bond distances ranging from 2.91–2.97 Å. There are a spread of Nb–Al bond distances ranging from 2.90–2.98 Å. There are three inequivalent Cr sites. In the first Cr site, Cr is bonded to six Nb and six Al atoms to form distorted CrNb6Al6 cuboctahedra that share corners with four equivalent AlNb6Al2Cr4 cuboctahedra, corners with fourteen CrNb6Al6 cuboctahedra, edges with six CrNb6Al6 cuboctahedra, faces with four equivalent CrNb6Al2Cr4 cuboctahedra, and faces with fourteen AlNb6Al2Cr4 cuboctahedra. There are a spread of Cr–Al bond distances ranging from 2.44–2.55 Å. In the second Cr site, Cr is bonded to six Nb, four Cr, and two equivalent Al atoms to form CrNb6Al2Cr4 cuboctahedra that share corners with eight CrNb6Al6 cuboctahedra, corners with ten AlNb6Al2Cr4 cuboctahedra, edges with two equivalent CrNb6Al2Cr4 cuboctahedra, edges with four equivalent AlNb6Al4Cr2 cuboctahedra, faces with eight AlNb6Al2Cr4 cuboctahedra, and faces with ten CrNb6Al6 cuboctahedra. There are a spread of Cr–Cr bond distances ranging from 2.37–2.61 Å. Both Cr–Al bond lengths are 2.53 Å. In the third Cr site, Cr is bonded to six Nb, four equivalent Cr, and two equivalent Al atoms to form CrNb6Al2Cr4 cuboctahedra that share corners with six CrNb6Al6 cuboctahedra, corners with twelve AlNb6Al2Cr4 cuboctahedra, edges with six CrNb6Al6 cuboctahedra, faces with eight equivalent CrNb6Al2Cr4 cuboctahedra, and faces with ten AlNb6Al2Cr4 cuboctahedra. Both Cr–Al bond lengths are 2.55 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded to six Nb, four Cr, and two equivalent Al atoms to form distorted AlNb6Al2Cr4 cuboctahedra that share corners with four equivalent AlNb6Al4Cr2 cuboctahedra, corners with eight CrNb6Al6 cuboctahedra, edges with six equivalent AlNb6Al2Cr4 cuboctahedra, faces with eight AlNb6Al2Cr4 cuboctahedra, and faces with twelve CrNb6Al6 cuboctahedra. Both Al–Al bond lengths are 2.61 Å. In the second Al site, Al is bonded to six Nb, two equivalent Cr, and four Al atoms to form distorted AlNb6Al4Cr2 cuboctahedra that share corners with eight AlNb6Al2Cr4 cuboctahedra, corners with ten CrNb6Al2Cr4 cuboctahedra, edges with two equivalent AlNb6Al4Cr2 cuboctahedra, edges with four equivalent CrNb6Al2Cr4 cuboctahedra, faces with eight CrNb6Al6 cuboctahedra, and faces with ten AlNb6Al2Cr4 cuboctahedra. There are one shorter (2.45 Å) and one longer (2.55 Å) Al–Al bond lengths.