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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Nb2V4Si5 by Materials Project

Nb2V4Si5 crystallizes in the orthorhombic Ibam space group. The structure is three-dimensional. Nb2+ is bonded to six Si+2.40- atoms to form distorted NbSi6 octahedra that share corners with four equivalent NbSi6 octahedra, corners with six equivalent VSi7 pentagonal bipyramids, edges with two equivalent NbSi6 octahedra, faces with two equivalent NbSi6 octahedra, and faces with four equivalent VSi7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 36°. There are a spread of Nb–Si bond distances ranging from 2.57–2.66 Å. There are two inequivalent V2+ sites. In the first V2+ site, V2+ is bonded to seven Si+2.40- atoms to form VSi7 pentagonal bipyramids that share corners with six equivalent NbSi6 octahedra, corners with six equivalent VSi7 pentagonal bipyramids, edges with three equivalent VSi7 pentagonal bipyramids, faces with four equivalent NbSi6 octahedra, and faces with two equivalent VSi7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 42–55°. There are a spread of V–Si bond distances ranging from 2.58–2.86 Å. In the second V2+ site, V2+ is bonded in a 7-coordinate geometry to seven Si+2.40- atoms. There are a spread of V–Si bond distances ranging from 2.35–2.83 Å. There are three inequivalent Si+2.40- sites. In the first Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to two equivalent Nb2+, five V2+, and one Si+2.40- atom. The Si–Si bond length is 2.42 Å. In the second Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to four equivalent Nb2+ and five V2+ atoms. In the third Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to eight V2+ and two equivalent Si+2.40- atoms. Both Si–Si bond lengths are 2.57 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Materials Data on Nb2(VSi)3 by Materials Project

Nb2(VSi)3 crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. Nb2+ is bonded to six equivalent Si4- atoms to form a mixture of edge, corner, and face-sharing NbSi6 octahedra. The corner-sharing octahedral tilt angles are 39°. All Nb–Si bond lengths are 2.64 Å. V+2.67+ is bonded in a 5-coordinate geometry to five equivalent Si4- atoms. There are a spread of V–Si bond distances ranging from 2.46–2.76 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Nb2+ and five equivalent V+2.67+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Materials Data on Nb4V2Si5 by Materials Project

Nb4V2Si5 crystallizes in the orthorhombic Ibam space group. The structure is three-dimensional. there are two inequivalent Nb2+ sites. In the first Nb2+ site, Nb2+ is bonded to seven Si+2.40- atoms to form a mixture of face, edge, and corner-sharing NbSi7 pentagonal bipyramids. There are a spread of Nb–Si bond distances ranging from 2.69–2.87 Å. In the second Nb2+ site, Nb2+ is bonded to seven Si+2.40- atoms to form a mixture of distorted face, edge, and corner-sharing NbSi7 pentagonal bipyramids. There are a spread of Nb–Si bond distances ranging from 2.52–2.82 Å. V2+ is bonded in a 8-coordinate geometry to two equivalent V2+ and six Si+2.40- atoms. Both V–V bond lengths are 2.51 Å. There are a spread of V–Si bond distances ranging from 2.48–2.68 Å. There are three inequivalent Si+2.40- sites. In the first Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to eight Nb2+ and two equivalent Si+2.40- atoms. Both Si–Si bond lengths are 2.51 Å. In the second Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to five Nb2+ and four equivalent V2+ atoms. In the third Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to five Nb2+, two equivalent V2+, and three equivalent Si+2.40- atoms. There are one shorter (2.59 Å) and two longer (2.83 Å) Si–Si bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NbVSi by Materials Project

NbVSi crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are two inequivalent Nb2+ sites. In the first Nb2+ site, Nb2+ is bonded in a 7-coordinate geometry to seven Si4- atoms. There are a spread of Nb–Si bond distances ranging from 2.88–2.94 Å. In the second Nb2+ site, Nb2+ is bonded to five Si4- atoms to form distorted NbSi5 trigonal bipyramids that share corners with six SiNb6V4Si2 cuboctahedra, corners with six equivalent NbSi5 trigonal bipyramids, edges with four equivalent SiNb6V2Si4 cuboctahedra, and an edgeedge with one NbSi5 trigonal bipyramid. There are a spread of Nb–Si bond distances ranging from 2.83–2.91 Å. There are three inequivalent V2+ sites. In the first V2+ site, V2+ is bonded in a hexagonal planar geometry to six Si4- atoms. There are two shorter (2.42 Å) and four longer (2.49 Å) V–Si bond lengths. In the second V2+ site, V2+ is bonded in a 6-coordinate geometry to four V2+ and two equivalent Si4- atoms. There are a spread of V–V bond distances ranging from 2.39–2.56 Å. Both V–Si bond lengths are 2.51 Å. In the third V2+ site, V2+ is bonded in a 6-coordinate geometry to four equivalent V2+ and two equivalent Si4- atoms. Both V–Si bond lengths are 2.51 Å. There are two inequivalent Si4- sites. In the first Si4- site, Si4- is bonded to six Nb2+, four V2+, and two equivalent Si4- atoms to form distorted SiNb6V4Si2 cuboctahedra that share corners with four equivalent SiNb6V2Si4 cuboctahedra, corners with four equivalent NbSi5 trigonal bipyramids, edges with six equivalent SiNb6V4Si2 cuboctahedra, and faces with eight SiNb6V4Si2 cuboctahedra. Both Si–Si bond lengths are 2.61 Å. In the second Si4- site, Si4- is bonded to six Nb2+, two equivalent V2+, and four Si4- atoms to form distorted SiNb6V2Si4 cuboctahedra that share corners with eight SiNb6V4Si2 cuboctahedra, corners with two equivalent NbSi5 trigonal bipyramids, edges with two equivalent SiNb6V2Si4 cuboctahedra, edges with four equivalent NbSi5 trigonal bipyramids, and faces with ten SiNb6V4Si2 cuboctahedra. There are one shorter (2.43 Å) and one longer (2.56 Å) Si–Si bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NbVSi4 by Materials Project

NbVSi4 is Titanium Disilicide-derived structured and crystallizes in the monoclinic P2 space group. The structure is three-dimensional. there are three inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded in a distorted q6 geometry to ten Si2- atoms. There are a spread of Nb–Si bond distances ranging from 2.62–2.76 Å. In the second Nb5+ site, Nb5+ is bonded in a distorted q6 geometry to ten Si2- atoms. There are a spread of Nb–Si bond distances ranging from 2.59–2.74 Å. In the third Nb5+ site, Nb5+ is bonded in a distorted q6 geometry to ten Si2- atoms. There are a spread of Nb–Si bond distances ranging from 2.60–2.76 Å. There are three inequivalent V3+ sites. In the first V3+ site, V3+ is bonded in a distorted q6 geometry to ten Si2- atoms. There are a spread of V–Si bond distances ranging from 2.51–2.77 Å. In the second V3+ site, V3+ is bonded in a distorted q6 geometry to ten Si2- atoms. There are a spread of V–Si bond distances ranging from 2.54–2.80 Å. In the third V3+ site, V3+ is bonded in a distorted q6 geometry to ten Si2- atoms. There are a spread of V–Si bond distances ranging from 2.51–2.77 Å. There are six inequivalent Si2- sites. In the first Si2- site, Si2- is bonded in a 10-coordinate geometry to four Nb5+, one V3+, and five Si2- atoms. There are a spread of Si–Si bond distances ranging from 2.53–2.82 Å. In the second Si2- site, Si2- is bonded in a 10-coordinate geometry to three equivalent Nb5+, two V3+, and five Si2- atoms. There are a spread of Si–Si bond distances ranging from 2.53–2.76 Å. In the third Si2- site, Si2- is bonded in a 10-coordinate geometry to four Nb5+, one V3+, and five Si2- atoms. There are a spread of Si–Si bond distances ranging from 2.52–2.81 Å. In the fourth Si2- site, Si2- is bonded in a 10-coordinate geometry to one Nb5+, four V3+, and five Si2- atoms. There are a spread of Si–Si bond distances ranging from 2.48–2.83 Å. In the fifth Si2- site, Si2- is bonded in a 10-coordinate geometry to two Nb5+, three equivalent V3+, and five Si2- atoms. There are one shorter (2.58 Å) and two longer (2.79 Å) Si–Si bond lengths. In the sixth Si2- site, Si2- is bonded in a 10-coordinate geometry to one Nb5+, four V3+, and five Si2- atoms. There are a spread of Si–Si bond distances ranging from 2.64–2.81 Å.

36 MATERIALS SCIENCE↗