Nb10(BSi)3 crystallizes in the orthorhombic Fmm2 space group. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 5-coordinate geometry to one B(1), one B(2), one Si(1), and two equivalent Si(2) atoms. In the second Nb site, Nb(2) is bonded to one B(2), two equivalent B(1), and two equivalent Si(2) atoms to form distorted NbSi2B3 trigonal bipyramids that share corners with two equivalent Nb(2)Si2B3 trigonal bipyramids, corners with two equivalent Nb(3)Si3B2 trigonal bipyramids, edges with three equivalent Nb(3)Si3B2 trigonal bipyramids, and  a faceface with one Nb(2)Si2B3 trigonal bipyramid. In the third Nb site, Nb(3) is bonded to two equivalent B(1), one Si(1), and two equivalent Si(2) atoms to form distorted NbSi3B2 trigonal bipyramids that share corners with two equivalent Nb(2)Si2B3 trigonal bipyramids, corners with two equivalent Nb(3)Si3B2 trigonal bipyramids, edges with three equivalent Nb(2)Si2B3 trigonal bipyramids, and  a faceface with one Nb(3)Si3B2 trigonal bipyramid. In the fourth Nb site, Nb(4) is bonded in a 4-coordinate geometry to one B(2), two equivalent B(1), one Si(1), and two equivalent Si(2) atoms. There are two inequivalent B sites. In the first B site, B(1) is bonded in a 9-coordinate geometry to two equivalent Nb(1), two equivalent Nb(2), two equivalent Nb(3), two equivalent Nb(4), and one B(1) atom. In the second B site, B(2) is bonded in a 9-coordinate geometry to two equivalent Nb(2), two equivalent Nb(4), four equivalent Nb(1), and one Si(1) atom. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Nb(3), two equivalent Nb(4), four equivalent Nb(1), and one B(2) atom. In the second Si site, Si(2) is bonded in a 10-coordinate geometry to two equivalent Nb(2), two equivalent Nb(3), two equivalent Nb(4), and four equivalent Nb(1) atoms.
Nb10(BSi)3 crystallizes in the orthorhombic Fmm2 space group. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 5-coordinate geometry to one B(1), one B(2), one Si(1), and two equivalent Si(2) atoms. The Nb(1)-B(1) bond length is 2.53 Å. The Nb(1)-B(2) bond length is 2.51 Å. The Nb(1)-Si(1) bond length is 2.54 Å. There is one shorter (2.67 Å) and one longer (2.69 Å) Nb(1)-Si(2) bond length. In the second Nb site, Nb(2) is bonded to one B(2), two equivalent B(1), and two equivalent Si(2) atoms to form distorted NbSi2B3 trigonal bipyramids that share corners with two equivalent Nb(2)Si2B3 trigonal bipyramids, corners with two equivalent Nb(3)Si3B2 trigonal bipyramids, edges with three equivalent Nb(3)Si3B2 trigonal bipyramids, and  a faceface with one Nb(2)Si2B3 trigonal bipyramid. The Nb(2)-B(2) bond length is 2.49 Å. Both Nb(2)-B(1) bond lengths are 2.44 Å. Both Nb(2)-Si(2) bond lengths are 2.69 Å. In the third Nb site, Nb(3) is bonded to two equivalent B(1), one Si(1), and two equivalent Si(2) atoms to form distorted NbSi3B2 trigonal bipyramids that share corners with two equivalent Nb(2)Si2B3 trigonal bipyramids, corners with two equivalent Nb(3)Si3B2 trigonal bipyramids, edges with three equivalent Nb(2)Si2B3 trigonal bipyramids, and  a faceface with one Nb(3)Si3B2 trigonal bipyramid. Both Nb(3)-B(1) bond lengths are 2.44 Å. The Nb(3)-Si(1) bond length is 2.61 Å. Both Nb(3)-Si(2) bond lengths are 2.72 Å. In the fourth Nb site, Nb(4) is bonded in a 4-coordinate geometry to one B(2), two equivalent B(1), one Si(1), and two equivalent Si(2) atoms. The Nb(4)-B(2) bond length is 2.48 Å. There is one shorter (2.55 Å) and one longer (2.57 Å) Nb(4)-B(1) bond length. The Nb(4)-Si(1) bond length is 2.57 Å. Both Nb(4)-Si(2) bond lengths are 2.94 Å. There are two inequivalent B sites. In the first B site, B(1) is bonded in a 9-coordinate geometry to two equivalent Nb(1), two equivalent Nb(2), two equivalent Nb(3), two equivalent Nb(4), and one B(1) atom. The B(1)-B(1) bond length is 2.06 Å. In the second B site, B(2) is bonded in a 9-coordinate geometry to two equivalent Nb(2), two equivalent Nb(4), four equivalent Nb(1), and one Si(1) atom. The B(2)-Si(1) bond length is 2.19 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Nb(3), two equivalent Nb(4), four equivalent Nb(1), and one B(2) atom. In the second Si site, Si(2) is bonded in a 10-coordinate geometry to two equivalent Nb(2), two equivalent Nb(3), two equivalent Nb(4), and four equivalent Nb(1) atoms.