Materials Data on NbCo by Materials Project

Abstract

NbCo is Frank-Kasper $\mu$ Phase-like structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are seven inequivalent Nb sites. In the first Nb site, Nb is bonded in a 6-coordinate geometry to three equivalent Nb and six Co atoms. All Nb–Nb bond lengths are 3.16 Å. There are three shorter (2.73 Å) and three longer (2.79 Å) Nb–Co bond lengths. In the second Nb site, Nb is bonded in a 6-coordinate geometry to three equivalent Nb and six Co atoms. All Nb–Nb bond lengths are 3.14 Å. All Nb–Co bond lengths are 2.74 Å. In the third Nb site, Nb is bonded in a 8-coordinate geometry to two Nb and six equivalent Co atoms. There are one shorter (2.64 Å) and one longer (2.72 Å) Nb–Nb bond lengths. All Nb–Co bond lengths are 2.67 Å. In the fourth Nb site, Nb is bonded in a 8-coordinate geometry to eight Nb and six equivalent Co atoms. The Nb–Nb bond length is 2.75 Å. All Nb–Co bond lengths are 2.68 Å. In the fifth Nb site, Nb is bonded in a 10-coordinate geometry to seven Nb and nine equivalent Co atoms. There are three shorter (2.88 Å) and three longer (2.95 Å) Nb–Nb bond lengths. There are three shorter (2.81 Å) and six longer (3.00 Å) Nb–Co bond lengths. In the sixth Nb site, Nb is bonded in a 6-coordinate geometry to four Nb and twelve Co atoms. All Nb–Nb bond lengths are 2.90 Å. There are a spread of Nb–Co bond distances ranging from 2.68–3.01 Å. In the seventh Nb site, Nb is bonded to six equivalent Nb and six equivalent Co atoms to form distorted NbNb6Co6 cuboctahedra that share corners with twelve equivalent CoNb8Co4 cuboctahedra, edges with six equivalent NbNb6Co6 cuboctahedra, and faces with eighteen equivalent CoNb8Co4 cuboctahedra. All Nb–Co bond lengths are 2.54 Å. There are three inequivalent Co sites. In the first Co site, Co is bonded to seven Nb and five Co atoms to form CoNb7Co5 cuboctahedra that share corners with fifteen CoNb7Co5 cuboctahedra, edges with five CoNb8Co4 cuboctahedra, and faces with thirteen CoNb7Co5 cuboctahedra. There are a spread of Co–Co bond distances ranging from 2.44–2.49 Å. In the second Co site, Co is bonded to eight Nb and four equivalent Co atoms to form distorted CoNb8Co4 cuboctahedra that share corners with two equivalent NbNb6Co6 cuboctahedra, corners with thirteen CoNb7Co5 cuboctahedra, edges with five CoNb7Co5 cuboctahedra, faces with three equivalent NbNb6Co6 cuboctahedra, and faces with ten equivalent CoNb8Co4 cuboctahedra. There are two shorter (2.41 Å) and two longer (2.53 Å) Co–Co bond lengths. In the third Co site, Co is bonded to six equivalent Nb and six equivalent Co atoms to form CoNb6Co6 cuboctahedra that share corners with twelve equivalent CoNb7Co5 cuboctahedra, edges with six equivalent CoNb6Co6 cuboctahedra, and faces with eighteen equivalent CoNb7Co5 cuboctahedra.