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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Nb3B3C by Materials Project

Nb3B3C crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are three inequivalent Nb+2.33+ sites. In the first Nb+2.33+ site, Nb+2.33+ 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 2.43–2.50 Å. In the second Nb+2.33+ site, Nb+2.33+ is bonded to one B1- and five equivalent C4- atoms to form distorted NbBC5 square pyramids that share corners with two equivalent NbB12 cuboctahedra, corners with four equivalent NbBC5 square pyramids, and edges with eight equivalent NbBC5 square pyramids. The Nb–B bond length is 2.90 Å. There are one shorter (2.17 Å) and four longer (2.27 Å) Nb–C bond lengths. In the third Nb+2.33+ site, Nb+2.33+ is bonded in a 1-coordinate geometry to six B1- and one C4- atom. There are two shorter (2.36 Å) and four longer (2.39 Å) Nb–B bond lengths. The Nb–C bond length is 2.15 Å. There are three inequivalent B1- sites. In the first B1- site, B1- is bonded in a 9-coordinate geometry to six equivalent Nb+2.33+ and three B1- atoms. There is two shorter (1.81 Å) and one longer (1.84 Å) B–B bond length. In the second B1- site, B1- is bonded in a 9-coordinate geometry to seven Nb+2.33+ and two equivalent B1- atoms. Both B–B bond lengths are 1.84 Å. In the third B1- site, B1- is bonded in a 9-coordinate geometry to six Nb+2.33+ and three B1- atoms. C4- is bonded to six Nb+2.33+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 1°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb4B3C2 by Materials Project

Nb4B3C2 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are four inequivalent Nb+2.75+ sites. In the first Nb+2.75+ site, Nb+2.75+ 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 2.43–2.49 Å. In the second Nb+2.75+ site, Nb+2.75+ is bonded in a 1-coordinate geometry to six B1- and one C4- atom. There are two shorter (2.36 Å) and four longer (2.39 Å) Nb–B bond lengths. The Nb–C bond length is 2.13 Å. In the third Nb+2.75+ site, Nb+2.75+ is bonded to six C4- atoms to form NbC6 octahedra that share corners with four equivalent NbC6 octahedra, a cornercorner with one NbBC5 square pyramid, edges with eight equivalent NbC6 octahedra, and edges with four equivalent NbBC5 square pyramids. The corner-sharing octahedral tilt angles are 1°. There are a spread of Nb–C bond distances ranging from 2.19–2.29 Å. In the fourth Nb+2.75+ site, Nb+2.75+ is bonded to one B1- and five C4- atoms to form NbBC5 square pyramids that share corners with two equivalent NbB12 cuboctahedra, a cornercorner with one NbC6 octahedra, corners with four equivalent NbBC5 square pyramids, edges with four equivalent NbC6 octahedra, and edges with four equivalent NbBC5 square pyramids. The corner-sharing octahedral tilt angles are 0°. The Nb–B bond length is 2.91 Å. There are one shorter (2.20 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+2.75+ and two equivalent B1- atoms. Both B–B bond lengths are 1.84 Å. In the second B1- site, B1- is bonded in a 9-coordinate geometry to six Nb+2.75+ and three B1- atoms. The B–B bond length is 1.84 Å. In the third B1- site, B1- is bonded in a 9-coordinate geometry to six equivalent Nb+2.75+ and three B1- atoms. Both B–B bond lengths are 1.81 Å. There are two inequivalent C4- sites. In the first C4- site, C4- is bonded to six Nb+2.75+ atoms to form a mixture of corner and edge-sharing CNb6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the second C4- site, C4- is bonded to six Nb+2.75+ atoms to form a mixture of corner and edge-sharing CNb6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb7(BC)4 by Materials Project

Nb(Nb3C2)2(B)4 crystallizes in the orthorhombic Immm space group. The structure is two-dimensional and consists of two niobium molecules; two B ribbons oriented in the (1, 0, 0) direction; and two Nb3C2 sheets oriented in the (0, 0, 1) direction. In each B ribbon, there are two inequivalent B sites. In the first B site, B is bonded in a 3-coordinate geometry to three B atoms. There is two shorter (1.83 Å) and one longer (1.85 Å) B–B bond length. In the second B site, B is bonded in a 2-coordinate geometry to two equivalent B atoms. In each Nb3C2 sheet, there are three inequivalent Nb+2.29+ sites. In the first Nb+2.29+ site, Nb+2.29+ is bonded in a single-bond geometry to one C4- atom. The Nb–C bond length is 2.14 Å. In the second Nb+2.29+ site, Nb+2.29+ is bonded to six C4- atoms to form NbC6 octahedra that share corners with four equivalent NbC6 octahedra, a cornercorner with one NbC5 square pyramid, edges with eight equivalent NbC6 octahedra, and edges with four equivalent NbC5 square pyramids. The corner-sharing octahedral tilt angles are 2°. There are a spread of Nb–C bond distances ranging from 2.19–2.29 Å. In the third Nb+2.29+ site, Nb+2.29+ is bonded to five C4- atoms to form NbC5 square pyramids that share a cornercorner with one NbC6 octahedra, corners with four equivalent NbC5 square pyramids, edges with four equivalent NbC6 octahedra, and edges with four equivalent NbC5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are one shorter (2.20 Å) and four longer (2.26 Å) Nb–C bond lengths. There are two inequivalent C4- sites. In the first C4- site, C4- is bonded to six Nb+2.29+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the second C4- site, C4- is bonded to six Nb+2.29+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb7(B2C)3 by Materials Project

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°.

36 MATERIALS SCIENCE↗