Nb5Si3 crystallizes in the tetragonal I4/mcm space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to two equivalent Si(2) and four equivalent Si(1) atoms. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to two equivalent Nb(2) and four equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 10-coordinate geometry to two equivalent Nb(2) and eight equivalent Nb(1) atoms. In the second Si site, Si(2) is bonded in a 10-coordinate geometry to eight equivalent Nb(1) and two equivalent Si(2) atoms.
Nb5Si3 crystallizes in the tetragonal I4/mcm space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to two equivalent Si(2) and four equivalent Si(1) atoms. Both Nb(1)-Si(2) bond lengths are 2.66 Å. There are a spread of Nb(1)-Si(1) bond distances ranging from 2.67-2.94 Å. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to two equivalent Nb(2) and four equivalent Si(1) atoms. Both Nb(2)-Nb(2) bond lengths are 2.55 Å. All Nb(2)-Si(1) bond lengths are 2.67 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 10-coordinate geometry to two equivalent Nb(2) and eight equivalent Nb(1) atoms. In the second Si site, Si(2) is bonded in a 10-coordinate geometry to eight equivalent Nb(1) and two equivalent Si(2) atoms. Both Si(2)-Si(2) bond lengths are 2.55 Å.