MgNb4(SnO6)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 3-coordinate geometry to one Sn(2), one O(12), one O(6), and one O(8) atom. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(10), one O(11), one O(2), one O(3), and one O(5) atom to form a mixture of distorted corner and edge-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 29-53°. In the second Nb site, Nb(2) is bonded to one O(1), one O(12), one O(2), one O(4), one O(6), and one O(9) atom to form a mixture of distorted corner and edge-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 32-53°. In the third Nb site, Nb(3) is bonded to one O(1), one O(12), one O(3), one O(4), one O(6), and one O(8) atom to form a mixture of distorted corner and edge-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 32-60°. In the fourth Nb site, Nb(4) is bonded to one O(11), one O(2), one O(3), one O(4), one O(5), and one O(7) atom to form a mixture of distorted corner and edge-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 29-60°. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a rectangular see-saw-like geometry to one O(10), one O(7), one O(8), and one O(9) atom. In the second Sn site, Sn(2) is bonded in a 5-coordinate geometry to one Mg(1), one O(10), one O(11), one O(7), and one O(8) atom. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Nb(1), one Nb(2), and one Nb(4) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Nb(1), one Nb(3), and one Nb(4) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Nb(2), one Nb(3), and one Nb(4) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Nb(1) and one Nb(4) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(1), one Nb(2), and one Nb(3) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Nb(4), one Sn(1), and one Sn(2) atom. In the eighth O site, O(8) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Nb(3), one Sn(1), and one Sn(2) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Nb(2) and one Sn(1) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Nb(1), one Sn(1), and one Sn(2) atom. In the eleventh O site, O(11) is bonded in a 2-coordinate geometry to one Nb(1), one Nb(4), and one Sn(2) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Mg(1), one Nb(2), and one Nb(3) atom.
MgNb4(SnO6)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 3-coordinate geometry to one Sn(2), one O(12), one O(6), and one O(8) atom. The Mg(1)-Sn(2) bond length is 2.65 Å. The Mg(1)-O(12) bond length is 1.95 Å. The Mg(1)-O(6) bond length is 2.06 Å. The Mg(1)-O(8) bond length is 1.96 Å. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(10), one O(11), one O(2), one O(3), and one O(5) atom to form a mixture of distorted corner and edge-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 29-53°. The Nb(1)-O(1) bond length is 2.08 Å. The Nb(1)-O(10) bond length is 2.11 Å. The Nb(1)-O(11) bond length is 2.18 Å. The Nb(1)-O(2) bond length is 1.93 Å. The Nb(1)-O(3) bond length is 2.17 Å. The Nb(1)-O(5) bond length is 2.04 Å. In the second Nb site, Nb(2) is bonded to one O(1), one O(12), one O(2), one O(4), one O(6), and one O(9) atom to form a mixture of distorted corner and edge-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 32-53°. The Nb(2)-O(1) bond length is 2.06 Å. The Nb(2)-O(12) bond length is 1.98 Å. The Nb(2)-O(2) bond length is 2.25 Å. The Nb(2)-O(4) bond length is 2.26 Å. The Nb(2)-O(6) bond length is 1.91 Å. The Nb(2)-O(9) bond length is 1.88 Å. In the third Nb site, Nb(3) is bonded to one O(1), one O(12), one O(3), one O(4), one O(6), and one O(8) atom to form a mixture of distorted corner and edge-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 32-60°. The Nb(3)-O(1) bond length is 2.08 Å. The Nb(3)-O(12) bond length is 2.16 Å. The Nb(3)-O(3) bond length is 2.03 Å. The Nb(3)-O(4) bond length is 1.92 Å. The Nb(3)-O(6) bond length is 2.28 Å. The Nb(3)-O(8) bond length is 2.29 Å. In the fourth Nb site, Nb(4) is bonded to one O(11), one O(2), one O(3), one O(4), one O(5), and one O(7) atom to form a mixture of distorted corner and edge-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 29-60°. The Nb(4)-O(11) bond length is 1.88 Å. The Nb(4)-O(2) bond length is 2.27 Å. The Nb(4)-O(3) bond length is 2.10 Å. The Nb(4)-O(4) bond length is 2.22 Å. The Nb(4)-O(5) bond length is 1.90 Å. The Nb(4)-O(7) bond length is 1.98 Å. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a rectangular see-saw-like geometry to one O(10), one O(7), one O(8), and one O(9) atom. The Sn(1)-O(10) bond length is 2.12 Å. The Sn(1)-O(7) bond length is 2.46 Å. The Sn(1)-O(8) bond length is 2.43 Å. The Sn(1)-O(9) bond length is 2.17 Å. In the second Sn site, Sn(2) is bonded in a 5-coordinate geometry to one Mg(1), one O(10), one O(11), one O(7), and one O(8) atom. The Sn(2)-O(10) bond length is 2.05 Å. The Sn(2)-O(11) bond length is 2.66 Å. The Sn(2)-O(7) bond length is 2.05 Å. The Sn(2)-O(8) bond length is 2.18 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Nb(1), one Nb(2), and one Nb(4) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Nb(1), one Nb(3), and one Nb(4) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Nb(2), one Nb(3), and one Nb(4) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Nb(1) and one Nb(4) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(1), one Nb(2), and one Nb(3) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Nb(4), one Sn(1), and one Sn(2) atom. In the eighth O site, O(8) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Nb(3), one Sn(1), and one Sn(2) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Nb(2) and one Sn(1) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Nb(1), one Sn(1), and one Sn(2) atom. In the eleventh O site, O(11) is bonded in a 2-coordinate geometry to one Nb(1), one Nb(4), and one Sn(2) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Mg(1), one Nb(2), and one Nb(3) atom.