SrNb6O16 crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded in a 9-coordinate geometry to one O(7), two equivalent O(1), two equivalent O(8), and four equivalent O(5) atoms. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(9) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(3)O6 octahedra, corners with two equivalent Nb(2)O6 octahedra, corners with three equivalent Nb(1)O6 octahedra, and  an edgeedge with one Nb(4)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 4-51°. In the second Nb site, Nb(2) is bonded to one O(1), one O(10), one O(3), one O(4), and two equivalent O(8) atoms to form distorted NbO6 octahedra that share  a cornercorner with one Nb(3)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, corners with three equivalent Nb(2)O6 octahedra, and  an edgeedge with one Nb(4)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 21-42°. In the third Nb site, Nb(3) is bonded to two equivalent O(10), two equivalent O(5), and two equivalent O(7) atoms to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Nb(2)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra, and  an edgeedge with one Nb(4)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 16-51°. In the fourth Nb site, Nb(4) is bonded to one O(2), two equivalent O(10), two equivalent O(4), and two equivalent O(6) atoms to form NbO7 pentagonal bipyramids that share corners with two equivalent Nb(4)O7 pentagonal bipyramids,  an edgeedge with one Nb(3)O6 octahedra, edges with two equivalent Nb(1)O6 octahedra, and edges with two equivalent Nb(2)O6 octahedra. There are ten inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1) and two equivalent Nb(2) atoms to form distorted corner-sharing OSr2Nb2 tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Nb(4) and two equivalent Nb(1) atoms. 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 distorted trigonal planar geometry to one Nb(1), one Nb(2), and one Nb(4) atom. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Sr(1), one Nb(1), and one Nb(3) atom. In the sixth O site, O(6) is bonded in a linear geometry to two equivalent Nb(4) atoms. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Sr(1) and two equivalent Nb(3) atoms. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Sr(1) and two equivalent Nb(2) atoms. In the ninth O site, O(9) is bonded in a linear geometry to two equivalent Nb(1) atoms. In the tenth O site, O(10) is bonded in a distorted T-shaped geometry to one Nb(2), one Nb(3), and one Nb(4) atom.
SrNb6O16 crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded in a 9-coordinate geometry to one O(7), two equivalent O(1), two equivalent O(8), and four equivalent O(5) atoms. The Sr(1)-O(7) bond length is 2.61 Å. Both Sr(1)-O(1) bond lengths are 2.59 Å. Both Sr(1)-O(8) bond lengths are 2.76 Å. All Sr(1)-O(5) bond lengths are 2.69 Å. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(9) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(3)O6 octahedra, corners with two equivalent Nb(2)O6 octahedra, corners with three equivalent Nb(1)O6 octahedra, and  an edgeedge with one Nb(4)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 4-51°. The Nb(1)-O(2) bond length is 2.07 Å. The Nb(1)-O(3) bond length is 2.01 Å. The Nb(1)-O(4) bond length is 2.09 Å. The Nb(1)-O(5) bond length is 1.95 Å. Both Nb(1)-O(9) bond lengths are 1.96 Å. In the second Nb site, Nb(2) is bonded to one O(1), one O(10), one O(3), one O(4), and two equivalent O(8) atoms to form distorted NbO6 octahedra that share  a cornercorner with one Nb(3)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, corners with three equivalent Nb(2)O6 octahedra, and  an edgeedge with one Nb(4)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 21-42°. The Nb(2)-O(1) bond length is 2.05 Å. The Nb(2)-O(10) bond length is 2.18 Å. The Nb(2)-O(3) bond length is 1.87 Å. The Nb(2)-O(4) bond length is 2.10 Å. Both Nb(2)-O(8) bond lengths are 1.99 Å. In the third Nb site, Nb(3) is bonded to two equivalent O(10), two equivalent O(5), and two equivalent O(7) atoms to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Nb(2)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra, and  an edgeedge with one Nb(4)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 16-51°. Both Nb(3)-O(10) bond lengths are 1.94 Å. Both Nb(3)-O(5) bond lengths are 2.12 Å. Both Nb(3)-O(7) bond lengths are 1.98 Å. In the fourth Nb site, Nb(4) is bonded to one O(2), two equivalent O(10), two equivalent O(4), and two equivalent O(6) atoms to form NbO7 pentagonal bipyramids that share corners with two equivalent Nb(4)O7 pentagonal bipyramids,  an edgeedge with one Nb(3)O6 octahedra, edges with two equivalent Nb(1)O6 octahedra, and edges with two equivalent Nb(2)O6 octahedra. The Nb(4)-O(2) bond length is 2.04 Å. Both Nb(4)-O(10) bond lengths are 2.20 Å. Both Nb(4)-O(4) bond lengths are 2.11 Å. Both Nb(4)-O(6) bond lengths are 1.96 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1) and two equivalent Nb(2) atoms to form distorted corner-sharing OSr2Nb2 tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Nb(4) and two equivalent Nb(1) atoms. 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 distorted trigonal planar geometry to one Nb(1), one Nb(2), and one Nb(4) atom. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Sr(1), one Nb(1), and one Nb(3) atom. In the sixth O site, O(6) is bonded in a linear geometry to two equivalent Nb(4) atoms. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Sr(1) and two equivalent Nb(3) atoms. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Sr(1) and two equivalent Nb(2) atoms. In the ninth O site, O(9) is bonded in a linear geometry to two equivalent Nb(1) atoms. In the tenth O site, O(10) is bonded in a distorted T-shaped geometry to one Nb(2), one Nb(3), and one Nb(4) atom.