MgLu2Nb2O8 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(2)O6 octahedra, edges with two equivalent Lu(1)O6 octahedra, edges with two equivalent Lu(2)O6 octahedra, and faces with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-50°. There are two inequivalent Lu sites. In the first Lu site, Lu(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form LuO6 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 Lu(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-53°. In the second Lu site, Lu(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form LuO6 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 Lu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-53°. 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(3) atoms to form NbO6 octahedra that share corners with four equivalent Lu(1)O6 octahedra, corners with four equivalent Lu(2)O6 octahedra, edges with two equivalent Nb(2)O6 octahedra, and faces with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-50°. In the second Nb site, Nb(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NbO6 octahedra that share corners with four equivalent Mg(1)O6 octahedra, corners with four equivalent Lu(1)O6 octahedra, corners with four equivalent Lu(2)O6 octahedra, and edges with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-53°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Lu(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 Lu(1), one Lu(2), and one Nb(1) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Lu(2), one Nb(1), and one Nb(2) atom. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Lu(1), one Lu(2), and one Nb(2) atom.
MgLu2Nb2O8 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(2)O6 octahedra, edges with two equivalent Lu(1)O6 octahedra, edges with two equivalent Lu(2)O6 octahedra, and faces with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-50°. Both Mg(1)-O(1) bond lengths are 2.09 Å. Both Mg(1)-O(2) bond lengths are 2.04 Å. Both Mg(1)-O(3) bond lengths are 2.12 Å. There are two inequivalent Lu sites. In the first Lu site, Lu(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form LuO6 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 Lu(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-53°. Both Lu(1)-O(1) bond lengths are 2.22 Å. Both Lu(1)-O(2) bond lengths are 2.23 Å. Both Lu(1)-O(4) bond lengths are 2.21 Å. In the second Lu site, Lu(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form LuO6 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 Lu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-53°. Both Lu(2)-O(2) bond lengths are 2.17 Å. Both Lu(2)-O(3) bond lengths are 2.22 Å. Both Lu(2)-O(4) bond lengths are 2.29 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(3) atoms to form NbO6 octahedra that share corners with four equivalent Lu(1)O6 octahedra, corners with four equivalent Lu(2)O6 octahedra, edges with two equivalent Nb(2)O6 octahedra, and faces with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-50°. Both Nb(1)-O(1) bond lengths are 2.10 Å. Both Nb(1)-O(2) bond lengths are 2.09 Å. Both Nb(1)-O(3) bond lengths are 2.13 Å. In the second Nb site, Nb(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NbO6 octahedra that share corners with four equivalent Mg(1)O6 octahedra, corners with four equivalent Lu(1)O6 octahedra, corners with four equivalent Lu(2)O6 octahedra, and edges with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-53°. Both Nb(2)-O(1) bond lengths are 2.26 Å. Both Nb(2)-O(3) bond lengths are 2.24 Å. Both Nb(2)-O(4) bond lengths are 1.99 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Lu(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 Lu(1), one Lu(2), and one Nb(1) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Lu(2), one Nb(1), and one Nb(2) atom. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Lu(1), one Lu(2), and one Nb(2) atom.