Nb10Al3Si3 crystallizes in the orthorhombic Fmm2 space group. There are five inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 2-coordinate geometry to two equivalent Al(1), one Si(1), and three equivalent Si(2) atoms. In the second Nb site, Nb(2) is bonded in a 1-coordinate geometry to one Al(2), two equivalent Al(1), and three equivalent Si(2) atoms. In the third Nb site, Nb(3) is bonded in a 2-coordinate geometry to two equivalent Al(1), two equivalent Al(2), one Si(1), and one Si(2) atom. In the fourth Nb site, Nb(4) is bonded in a 1-coordinate geometry to one Al(2), two equivalent Al(1), one Si(2), and two equivalent Si(1) atoms. In the fifth Nb site, Nb(5) is bonded in a 6-coordinate geometry to two equivalent Nb(5), one Al(2), one Si(1), and two equivalent Si(2) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a distorted q6 geometry to two equivalent Nb(1), two equivalent Nb(2), two equivalent Nb(3), two equivalent Nb(4), and two equivalent Al(1) atoms. In the second Al site, Al(2) is bonded in a distorted q6 geometry to two equivalent Nb(2), two equivalent Nb(4), two equivalent Nb(5), and four equivalent Nb(3) 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(1), two equivalent Nb(3), two equivalent Nb(5), and four equivalent Nb(4) atoms. In the second Si site, Si(2) is bonded in a 10-coordinate geometry to one Nb(3), one Nb(4), two equivalent Nb(5), three equivalent Nb(1), and three equivalent Nb(2) atoms.
Nb10Al3Si3 crystallizes in the orthorhombic Fmm2 space group. There are five inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 2-coordinate geometry to two equivalent Al(1), one Si(1), and three equivalent Si(2) atoms. Both Nb(1)-Al(1) bond lengths are 2.75 Å. The Nb(1)-Si(1) bond length is 2.73 Å. There is one shorter (2.72 Å) and two longer (2.96 Å) Nb(1)-Si(2) bond lengths. In the second Nb site, Nb(2) is bonded in a 1-coordinate geometry to one Al(2), two equivalent Al(1), and three equivalent Si(2) atoms. The Nb(2)-Al(2) bond length is 2.77 Å. Both Nb(2)-Al(1) bond lengths are 2.75 Å. There is one shorter (2.67 Å) and two longer (2.95 Å) Nb(2)-Si(2) bond lengths. In the third Nb site, Nb(3) is bonded in a 2-coordinate geometry to two equivalent Al(1), two equivalent Al(2), one Si(1), and one Si(2) atom. Both Nb(3)-Al(1) bond lengths are 2.74 Å. Both Nb(3)-Al(2) bond lengths are 2.96 Å. The Nb(3)-Si(1) bond length is 2.71 Å. The Nb(3)-Si(2) bond length is 2.70 Å. In the fourth Nb site, Nb(4) is bonded in a 1-coordinate geometry to one Al(2), two equivalent Al(1), one Si(2), and two equivalent Si(1) atoms. The Nb(4)-Al(2) bond length is 2.75 Å. Both Nb(4)-Al(1) bond lengths are 2.75 Å. The Nb(4)-Si(2) bond length is 2.68 Å. Both Nb(4)-Si(1) bond lengths are 2.96 Å. In the fifth Nb site, Nb(5) is bonded in a 6-coordinate geometry to two equivalent Nb(5), one Al(2), one Si(1), and two equivalent Si(2) atoms. There is one shorter (2.57 Å) and one longer (2.59 Å) Nb(5)-Nb(5) bond length. The Nb(5)-Al(2) bond length is 2.74 Å. The Nb(5)-Si(1) bond length is 2.70 Å. Both Nb(5)-Si(2) bond lengths are 2.69 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a distorted q6 geometry to two equivalent Nb(1), two equivalent Nb(2), two equivalent Nb(3), two equivalent Nb(4), and two equivalent Al(1) atoms. Both Al(1)-Al(1) bond lengths are 2.58 Å. In the second Al site, Al(2) is bonded in a distorted q6 geometry to two equivalent Nb(2), two equivalent Nb(4), two equivalent Nb(5), and four equivalent Nb(3) 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(1), two equivalent Nb(3), two equivalent Nb(5), and four equivalent Nb(4) atoms. In the second Si site, Si(2) is bonded in a 10-coordinate geometry to one Nb(3), one Nb(4), two equivalent Nb(5), three equivalent Nb(1), and three equivalent Nb(2) atoms.