Materials Data on Nb7(B2C)3 by Materials Project

Abstract

Nb7(B2C)3 crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. there are four inequivalent Nb+2.57+ sites. In the first Nb+2.57+ site, Nb+2.57+ is bonded to twelve B1- atoms to form NbB12 cuboctahedra that share corners with two equivalent NbBC5 square pyramids, edges with eight equivalent NbB12 cuboctahedra, and faces with six equivalent NbB12 cuboctahedra. There are a spread of Nb–B bond distances ranging from 2.43–2.51 Å. In the second Nb+2.57+ site, Nb+2.57+ is bonded to one B1- and five C4- atoms to form distorted NbBC5 square pyramids that share corners with two equivalent NbB12 cuboctahedra, corners with five equivalent NbBC5 square pyramids, edges with four equivalent NbC6 octahedra, and edges with four equivalent NbBC5 square pyramids. The Nb–B bond length is 2.85 Å. There are one shorter (2.24 Å) and four longer (2.27 Å) Nb–C bond lengths. In the third Nb+2.57+ site, Nb+2.57+ is bonded in a 1-coordinate geometry to six B1- and one C4- atom. There are two shorter (2.36 Å) and four longer (2.38 Å) Nb–B bond lengths. The Nb–C bond length is 2.15 Å. In the fourth Nb+2.57+ site, Nb+2.57+ is bonded to six C4- atoms to form NbC6 octahedra that share corners with four equivalent NbC6 octahedra, edges with four equivalent NbC6 octahedra, and edges with eight equivalent NbBC5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.21 Å) and four longer (2.27 Å) Nb–C bond lengths. There are three inequivalent B1- sites. In the first B1- site, B1- is bonded in a 9-coordinate geometry to seven Nb+2.57+ and two equivalent B1- atoms. Both B–B bond lengths are 1.85 Å. In the second B1- site, B1- is bonded in a 9-coordinate geometry to six equivalent Nb+2.57+ and three B1- atoms. There is two shorter (1.81 Å) and one longer (1.83 Å) B–B bond length. In the third B1- site, B1- is bonded in a 9-coordinate geometry to six Nb+2.57+ and three B1- atoms. There are two inequivalent C4- sites. In the first C4- site, C4- is bonded to six Nb+2.57+ atoms to form a mixture of corner and edge-sharing CNb6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the second C4- site, C4- is bonded to six Nb+2.57+ atoms to form a mixture of corner and edge-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 0°.