Materials Data on Nb3Cr8Si by Materials Project

Abstract

Nb3Cr8Si is Hexagonal Laves-derived structured and crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. there are three inequivalent Nb sites. In the first Nb site, Nb is bonded in a 3-coordinate geometry to one Nb, twelve Cr, and three equivalent Si atoms. The Nb–Nb bond length is 3.06 Å. There are a spread of Nb–Cr bond distances ranging from 2.77–2.86 Å. All Nb–Si bond lengths are 2.95 Å. In the second Nb site, Nb is bonded in a 12-coordinate geometry to four Nb and twelve Cr atoms. All Nb–Nb bond lengths are 2.98 Å. There are a spread of Nb–Cr bond distances ranging from 2.84–2.87 Å. In the third Nb site, Nb is bonded in a 1-coordinate geometry to three equivalent Nb, twelve Cr, and one Si atom. There are a spread of Nb–Cr bond distances ranging from 2.84–2.89 Å. The Nb–Si bond length is 2.94 Å. There are four inequivalent Cr sites. In the first Cr site, Cr is bonded to three equivalent Nb, six Cr, and three equivalent Si atoms to form CrNb3Cr6Si3 cuboctahedra that share corners with twelve CrNb4Cr6Si2 cuboctahedra, edges with six equivalent CrNb3Cr6Si3 cuboctahedra, and faces with twenty CrNb6Cr6 cuboctahedra. There are three shorter (2.42 Å) and three longer (2.43 Å) Cr–Cr bond lengths. All Cr–Si bond lengths are 2.85 Å. In the second Cr site, Cr is bonded to six Nb and six Cr atoms to form CrNb6Cr6 cuboctahedra that share corners with twelve CrNb4Cr6Si2 cuboctahedra, edges with six equivalent CrNb6Cr6 cuboctahedra, and faces with twenty CrNb3Cr6Si3 cuboctahedra. All Cr–Cr bond lengths are 2.47 Å. In the third Cr site, Cr is bonded to four Nb, six Cr, and two equivalent Si atoms to form CrNb4Cr6Si2 cuboctahedra that share corners with eighteen CrNb3Cr6Si3 cuboctahedra, edges with six CrNb5Cr6Si cuboctahedra, and faces with eighteen CrNb3Cr6Si3 cuboctahedra. There are two shorter (2.39 Å) and two longer (2.46 Å) Cr–Cr bond lengths. Both Cr–Si bond lengths are 2.83 Å. In the fourth Cr site, Cr is bonded to five Nb, six Cr, and one Si atom to form CrNb5Cr6Si cuboctahedra that share corners with eighteen CrNb3Cr6Si3 cuboctahedra, edges with six CrNb5Cr6Si cuboctahedra, and faces with eighteen CrNb3Cr6Si3 cuboctahedra. There are two shorter (2.36 Å) and two longer (2.49 Å) Cr–Cr bond lengths. The Cr–Si bond length is 2.82 Å. Si is bonded in a 9-coordinate geometry to four Nb and twelve Cr atoms.