Nb3SiO10 crystallizes in the triclinic P1 space group. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form NbO6 octahedra that share corners with three equivalent Nb(3)O6 octahedra and  an edgeedge with one Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-55°. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one O(10), one O(3), one O(4), one O(5), one O(6), and one O(7) atom. In the third Nb site, Nb(3) is bonded to one O(1), one O(10), one O(2), one O(4), one O(8), and one O(9) atom to form distorted NbO6 octahedra that share corners with three equivalent Nb(1)O6 octahedra and corners with four equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 24-55°. Si(1) is bonded to one O(1), one O(10), one O(2), one O(6), one O(7), and one O(9) atom to form SiO6 octahedra that share corners with four equivalent Nb(3)O6 octahedra and  an edgeedge with one Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 24-48°. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Nb(1), one Nb(3), and one Si(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Nb(3) and one Si(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Nb(1) and one Nb(2) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Nb(1) and one Nb(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Nb(1), one Nb(2), and one Si(1) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Nb(2) and one Si(1) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Nb(1) and one Nb(3) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Nb(3) and one Si(1) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Nb(2), one Nb(3), and one Si(1) atom.
Nb3SiO10 crystallizes in the triclinic P1 space group. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form NbO6 octahedra that share corners with three equivalent Nb(3)O6 octahedra and  an edgeedge with one Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-55°. The Nb(1)-O(1) bond length is 2.15 Å. The Nb(1)-O(3) bond length is 1.87 Å. The Nb(1)-O(4) bond length is 2.00 Å. The Nb(1)-O(5) bond length is 2.04 Å. The Nb(1)-O(6) bond length is 2.13 Å. The Nb(1)-O(8) bond length is 1.91 Å. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one O(10), one O(3), one O(4), one O(5), one O(6), and one O(7) atom. The Nb(2)-O(10) bond length is 2.58 Å. The Nb(2)-O(3) bond length is 1.98 Å. The Nb(2)-O(4) bond length is 2.15 Å. The Nb(2)-O(5) bond length is 1.85 Å. The Nb(2)-O(6) bond length is 2.05 Å. The Nb(2)-O(7) bond length is 1.87 Å. In the third Nb site, Nb(3) is bonded to one O(1), one O(10), one O(2), one O(4), one O(8), and one O(9) atom to form distorted NbO6 octahedra that share corners with three equivalent Nb(1)O6 octahedra and corners with four equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 24-55°. The Nb(3)-O(1) bond length is 2.13 Å. The Nb(3)-O(10) bond length is 2.24 Å. The Nb(3)-O(2) bond length is 1.85 Å. The Nb(3)-O(4) bond length is 2.14 Å. The Nb(3)-O(8) bond length is 1.96 Å. The Nb(3)-O(9) bond length is 1.93 Å. Si(1) is bonded to one O(1), one O(10), one O(2), one O(6), one O(7), and one O(9) atom to form SiO6 octahedra that share corners with four equivalent Nb(3)O6 octahedra and  an edgeedge with one Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 24-48°. The Si(1)-O(1) bond length is 1.83 Å. The Si(1)-O(10) bond length is 1.82 Å. The Si(1)-O(2) bond length is 1.80 Å. The Si(1)-O(6) bond length is 1.87 Å. The Si(1)-O(7) bond length is 1.79 Å. The Si(1)-O(9) bond length is 1.76 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Nb(1), one Nb(3), and one Si(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Nb(3) and one Si(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Nb(1) and one Nb(2) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Nb(1) and one Nb(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Nb(1), one Nb(2), and one Si(1) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Nb(2) and one Si(1) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Nb(1) and one Nb(3) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Nb(3) and one Si(1) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Nb(2), one Nb(3), and one Si(1) atom.