Materials Data on Nb3Co4B7 by Materials Project

Abstract

Nb3Co4B7 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Nb+2.33+ sites. In the first Nb+2.33+ site, Nb+2.33+ is bonded to eight B+2.14- atoms to form NbB8 hexagonal bipyramids that share corners with four equivalent CoB4 tetrahedra, edges with six equivalent CoB4 tetrahedra, and faces with two equivalent NbB8 hexagonal bipyramids. There are four shorter (2.46 Å) and four longer (2.51 Å) Nb–B bond lengths. In the second Nb+2.33+ site, Nb+2.33+ is bonded in a distorted q4 geometry to nine B+2.14- atoms. There are a spread of Nb–B bond distances ranging from 2.40–2.51 Å. There are three inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded in a 10-coordinate geometry to ten B+2.14- atoms. There are a spread of Co–B bond distances ranging from 2.18–2.26 Å. In the second Co2+ site, Co2+ is bonded in a 5-coordinate geometry to five B+2.14- atoms. There are one shorter (2.05 Å) and four longer (2.10 Å) Co–B bond lengths. In the third Co2+ site, Co2+ is bonded to four B+2.14- atoms to form CoB4 tetrahedra that share corners with two equivalent NbB8 hexagonal bipyramids, corners with two equivalent CoB4 tetrahedra, edges with three equivalent NbB8 hexagonal bipyramids, and edges with two equivalent CoB4 tetrahedra. There are two shorter (2.08 Å) and two longer (2.09 Å) Co–B bond lengths. There are four inequivalent B+2.14- sites. In the first B+2.14- site, B+2.14- is bonded in a 9-coordinate geometry to three Nb+2.33+, five Co2+, and one B+2.14- atom. The B–B bond length is 1.87 Å. In the second B+2.14- site, B+2.14- is bonded in a 9-coordinate geometry to four equivalent Nb+2.33+, two equivalent Co2+, and three B+2.14- atoms. There are a spread of B–B bond distances ranging from 1.75–1.80 Å. In the third B+2.14- site, B+2.14- is bonded in a 9-coordinate geometry to four equivalent Nb+2.33+, three Co2+, and two equivalent B+2.14- atoms. In the fourth B+2.14- site, B+2.14- is bonded in a 9-coordinate geometry to four Nb+2.33+, three Co2+, and two B+2.14- atoms. The B–B bond length is 1.82 Å.