Materials Data on Nb6Co7 by Materials Project

Abstract

Co7Nb6 is Frank-Kasper $\mu$ Phase structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are three inequivalent Nb sites. In the first Nb site, Nb is bonded in a 6-coordinate geometry to nine Nb and six equivalent Co atoms. There are a spread of Nb–Nb bond distances ranging from 2.83–3.14 Å. There are three shorter (2.73 Å) and three longer (2.80 Å) Nb–Co bond lengths. In the second Nb site, Nb is bonded in a 6-coordinate geometry to four Nb and twelve Co atoms. There are one shorter (2.75 Å) and three longer (2.88 Å) Nb–Nb bond lengths. There are a spread of Nb–Co bond distances ranging from 2.67–2.99 Å. In the third Nb site, Nb is bonded in a 8-coordinate geometry to eight Nb and six equivalent Co atoms. The Nb–Nb bond length is 2.68 Å. All Nb–Co bond lengths are 2.66 Å. There are two inequivalent Co sites. In the first 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. All Co–Co bond lengths are 2.43 Å. In the second Co site, Co is bonded to seven Nb and five Co atoms to form CoNb7Co5 cuboctahedra that share corners with fifteen CoNb6Co6 cuboctahedra, edges with five equivalent CoNb7Co5 cuboctahedra, and faces with thirteen CoNb6Co6 cuboctahedra. There are two shorter (2.43 Å) and two longer (2.47 Å) Co–Co bond lengths.