Nb4V2Si5 crystallizes in the orthorhombic Ibam space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one Si(2), two equivalent Si(3), and four equivalent Si(1) atoms to form a mixture of distorted corner, edge, and face-sharing NbSi7 pentagonal bipyramids. In the second Nb site, Nb(2) is bonded in a 7-coordinate geometry to one Si(1), two equivalent Si(3), and four equivalent Si(2) atoms. V(1) is bonded in a 8-coordinate geometry to two equivalent V(1), two equivalent Si(2), and four equivalent Si(1) atoms. There are three inequivalent Si sites. In the first Si site, Si(3) is bonded in a 10-coordinate geometry to four equivalent Nb(1), four equivalent Nb(2), and two equivalent Si(3) atoms. In the second Si site, Si(1) is bonded in a 9-coordinate geometry to one Nb(2), four equivalent Nb(1), and four equivalent V(1) atoms. In the third Si site, Si(2) is bonded in a 10-coordinate geometry to one Nb(1), four equivalent Nb(2), two equivalent V(1), and three equivalent Si(2) atoms.
Nb4V2Si5 crystallizes in the orthorhombic Ibam space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one Si(2), two equivalent Si(3), and four equivalent Si(1) atoms to form a mixture of distorted corner, edge, and face-sharing NbSi7 pentagonal bipyramids. The Nb(1)-Si(2) bond length is 2.69 Å. Both Nb(1)-Si(3) bond lengths are 2.82 Å. There are a spread of Nb(1)-Si(1) bond distances ranging from 2.68-2.87 Å. In the second Nb site, Nb(2) is bonded in a 7-coordinate geometry to one Si(1), two equivalent Si(3), and four equivalent Si(2) atoms. The Nb(2)-Si(1) bond length is 2.55 Å. Both Nb(2)-Si(3) bond lengths are 2.59 Å. There are a spread of Nb(2)-Si(2) bond distances ranging from 2.51-2.81 Å. V(1) is bonded in a 8-coordinate geometry to two equivalent V(1), two equivalent Si(2), and four equivalent Si(1) atoms. Both V(1)-V(1) bond lengths are 2.50 Å. Both V(1)-Si(2) bond lengths are 2.48 Å. There are two shorter (2.54 Å) and two longer (2.67 Å) V(1)-Si(1) bond lengths. There are three inequivalent Si sites. In the first Si site, Si(3) is bonded in a 10-coordinate geometry to four equivalent Nb(1), four equivalent Nb(2), and two equivalent Si(3) atoms. Both Si(3)-Si(3) bond lengths are 2.50 Å. In the second Si site, Si(1) is bonded in a 9-coordinate geometry to one Nb(2), four equivalent Nb(1), and four equivalent V(1) atoms. In the third Si site, Si(2) is bonded in a 10-coordinate geometry to one Nb(1), four equivalent Nb(2), two equivalent V(1), and three equivalent Si(2) atoms. There is one shorter (2.56 Å) and two longer (2.82 Å) Si(2)-Si(2) bond lengths.