MgSc2Nb2O8 is beta indium sulfide-derived structured and crystallizes in the monoclinic P2 space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with four equivalent Nb(1)O6 octahedra, edges with two equivalent Sc(1)O6 octahedra, edges with two equivalent Sc(2)O6 octahedra, and faces with two equivalent Nb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-53°. There are two inequivalent Sc sites. In the first Sc site, Sc(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form ScO6 octahedra that share corners with four equivalent Nb(1)O6 octahedra, corners with four equivalent Nb(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Sc(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-53°. In the second Sc site, Sc(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form ScO6 octahedra that share corners with four equivalent Nb(1)O6 octahedra, corners with four equivalent Nb(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Sc(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-50°. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form NbO6 octahedra that share corners with four equivalent Mg(1)O6 octahedra, corners with four equivalent Sc(1)O6 octahedra, corners with four equivalent Sc(2)O6 octahedra, and edges with two equivalent Nb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-53°. In the second Nb site, Nb(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NbO6 octahedra that share corners with four equivalent Sc(1)O6 octahedra, corners with four equivalent Sc(2)O6 octahedra, edges with two equivalent Nb(1)O6 octahedra, and faces with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-48°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Sc(1), one Nb(1), and one Nb(2) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Sc(2), one Nb(1), and one Nb(2) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Sc(1), one Sc(2), and one Nb(2) atom. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Sc(1), one Sc(2), and one Nb(1) atom.
MgSc2Nb2O8 is beta indium sulfide-derived structured and crystallizes in the monoclinic P2 space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with four equivalent Nb(1)O6 octahedra, edges with two equivalent Sc(1)O6 octahedra, edges with two equivalent Sc(2)O6 octahedra, and faces with two equivalent Nb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-53°. Both Mg(1)-O(1) bond lengths are 2.04 Å. Both Mg(1)-O(2) bond lengths are 2.11 Å. Both Mg(1)-O(3) bond lengths are 2.04 Å. There are two inequivalent Sc sites. In the first Sc site, Sc(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form ScO6 octahedra that share corners with four equivalent Nb(1)O6 octahedra, corners with four equivalent Nb(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Sc(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-53°. Both Sc(1)-O(1) bond lengths are 2.16 Å. Both Sc(1)-O(3) bond lengths are 2.14 Å. Both Sc(1)-O(4) bond lengths are 2.12 Å. In the second Sc site, Sc(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form ScO6 octahedra that share corners with four equivalent Nb(1)O6 octahedra, corners with four equivalent Nb(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Sc(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-50°. Both Sc(2)-O(2) bond lengths are 2.16 Å. Both Sc(2)-O(3) bond lengths are 2.08 Å. Both Sc(2)-O(4) bond lengths are 2.19 Å. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form NbO6 octahedra that share corners with four equivalent Mg(1)O6 octahedra, corners with four equivalent Sc(1)O6 octahedra, corners with four equivalent Sc(2)O6 octahedra, and edges with two equivalent Nb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-53°. Both Nb(1)-O(1) bond lengths are 2.22 Å. Both Nb(1)-O(2) bond lengths are 2.22 Å. Both Nb(1)-O(4) bond lengths are 1.99 Å. In the second Nb site, Nb(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NbO6 octahedra that share corners with four equivalent Sc(1)O6 octahedra, corners with four equivalent Sc(2)O6 octahedra, edges with two equivalent Nb(1)O6 octahedra, and faces with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-48°. Both Nb(2)-O(1) bond lengths are 2.10 Å. Both Nb(2)-O(2) bond lengths are 2.12 Å. Both Nb(2)-O(3) bond lengths are 2.07 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Sc(1), one Nb(1), and one Nb(2) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Sc(2), one Nb(1), and one Nb(2) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Sc(1), one Sc(2), and one Nb(2) atom. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Sc(1), one Sc(2), and one Nb(1) atom.