MgEr2Tl2(WO4)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a distorted rectangular see-saw-like geometry to one Tl(2), one O(15), one O(3), one O(4), and one O(7) atom. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 6-coordinate geometry to one O(11), one O(13), one O(15), one O(6), one O(8), and one O(9) atom. In the second Er site, Er(2) is bonded in a 6-coordinate geometry to one O(10), one O(12), one O(14), one O(16), one O(5), and one O(7) atom. There are four inequivalent W sites. In the first W site, W(1) is bonded to one O(1), one O(10), one O(13), one O(4), one O(7), and one O(9) atom to form a mixture of corner and edge-sharing WO6 octahedra. The corner-sharing octahedral tilt angles range from 42-50°. In the second W site, W(2) is bonded to one O(10), one O(14), one O(2), one O(3), one O(8), and one O(9) atom to form a mixture of corner and edge-sharing WO6 octahedra. The corner-sharing octahedral tilt angles range from 40-48°. In the third W site, W(3) is bonded to one O(11), one O(12), one O(15), one O(2), one O(3), and one O(5) atom to form a mixture of corner and edge-sharing WO6 octahedra. The corner-sharing octahedral tilt angles range from 40-48°. In the fourth W site, W(4) is bonded to one O(1), one O(11), one O(12), one O(16), one O(4), and one O(6) atom to form a mixture of corner and edge-sharing WO6 octahedra. The corner-sharing octahedral tilt angles range from 42-50°. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a 3-coordinate geometry to one O(1), one O(2), and one O(5) atom. In the second Tl site, Tl(2) is bonded in a 4-coordinate geometry to one Mg(1), one O(1), one O(13), and one O(2) atom. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one W(1), one W(4), one Tl(1), and one Tl(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one W(2), one W(3), one Tl(1), and one Tl(2) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Mg(1), one W(2), and one W(3) atom. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Mg(1), one W(1), and one W(4) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Er(2), one W(3), and one Tl(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Er(1) and one W(4) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Mg(1), one Er(2), and one W(1) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Er(1) and one W(2) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Er(1), one W(1), and one W(2) atom. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Er(2), one W(1), and one W(2) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal non-coplanar geometry to one Er(1), one W(3), and one W(4) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Er(2), one W(3), and one W(4) atom. In the thirteenth O site, O(13) is bonded in a distorted T-shaped geometry to one Er(1), one W(1), and one Tl(2) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 150 degrees geometry to one Er(2) and one W(2) atom. In the fifteenth O site, O(15) is bonded in a distorted T-shaped geometry to one Mg(1), one Er(1), and one W(3) atom. In the sixteenth O site, O(16) is bonded in a bent 150 degrees geometry to one Er(2) and one W(4) atom.
MgEr2Tl2(WO4)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a distorted rectangular see-saw-like geometry to one Tl(2), one O(15), one O(3), one O(4), and one O(7) atom. The Mg(1)-Tl(2) bond length is 2.85 Å. The Mg(1)-O(15) bond length is 2.03 Å. The Mg(1)-O(3) bond length is 2.03 Å. The Mg(1)-O(4) bond length is 2.07 Å. The Mg(1)-O(7) bond length is 1.98 Å. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 6-coordinate geometry to one O(11), one O(13), one O(15), one O(6), one O(8), and one O(9) atom. The Er(1)-O(11) bond length is 2.29 Å. The Er(1)-O(13) bond length is 2.27 Å. The Er(1)-O(15) bond length is 2.21 Å. The Er(1)-O(6) bond length is 2.31 Å. The Er(1)-O(8) bond length is 2.27 Å. The Er(1)-O(9) bond length is 2.34 Å. In the second Er site, Er(2) is bonded in a 6-coordinate geometry to one O(10), one O(12), one O(14), one O(16), one O(5), and one O(7) atom. The Er(2)-O(10) bond length is 2.32 Å. The Er(2)-O(12) bond length is 2.28 Å. The Er(2)-O(14) bond length is 2.25 Å. The Er(2)-O(16) bond length is 2.28 Å. The Er(2)-O(5) bond length is 2.35 Å. The Er(2)-O(7) bond length is 2.22 Å. There are four inequivalent W sites. In the first W site, W(1) is bonded to one O(1), one O(10), one O(13), one O(4), one O(7), and one O(9) atom to form a mixture of corner and edge-sharing WO6 octahedra. The corner-sharing octahedral tilt angles range from 42-50°. The W(1)-O(1) bond length is 2.03 Å. The W(1)-O(10) bond length is 2.08 Å. The W(1)-O(13) bond length is 1.86 Å. The W(1)-O(4) bond length is 2.11 Å. The W(1)-O(7) bond length is 1.99 Å. The W(1)-O(9) bond length is 2.08 Å. In the second W site, W(2) is bonded to one O(10), one O(14), one O(2), one O(3), one O(8), and one O(9) atom to form a mixture of corner and edge-sharing WO6 octahedra. The corner-sharing octahedral tilt angles range from 40-48°. The W(2)-O(10) bond length is 2.08 Å. The W(2)-O(14) bond length is 1.85 Å. The W(2)-O(2) bond length is 1.96 Å. The W(2)-O(3) bond length is 2.03 Å. The W(2)-O(8) bond length is 1.83 Å. The W(2)-O(9) bond length is 2.11 Å. In the third W site, W(3) is bonded to one O(11), one O(12), one O(15), one O(2), one O(3), and one O(5) atom to form a mixture of corner and edge-sharing WO6 octahedra. The corner-sharing octahedral tilt angles range from 40-48°. The W(3)-O(11) bond length is 2.13 Å. The W(3)-O(12) bond length is 2.03 Å. The W(3)-O(15) bond length is 1.98 Å. The W(3)-O(2) bond length is 2.05 Å. The W(3)-O(3) bond length is 2.10 Å. The W(3)-O(5) bond length is 1.86 Å. In the fourth W site, W(4) is bonded to one O(1), one O(11), one O(12), one O(16), one O(4), and one O(6) atom to form a mixture of corner and edge-sharing WO6 octahedra. The corner-sharing octahedral tilt angles range from 42-50°. The W(4)-O(1) bond length is 2.00 Å. The W(4)-O(11) bond length is 2.00 Å. The W(4)-O(12) bond length is 2.13 Å. The W(4)-O(16) bond length is 1.84 Å. The W(4)-O(4) bond length is 2.01 Å. The W(4)-O(6) bond length is 1.87 Å. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a 3-coordinate geometry to one O(1), one O(2), and one O(5) atom. The Tl(1)-O(1) bond length is 2.80 Å. The Tl(1)-O(2) bond length is 2.76 Å. The Tl(1)-O(5) bond length is 2.79 Å. In the second Tl site, Tl(2) is bonded in a 4-coordinate geometry to one Mg(1), one O(1), one O(13), and one O(2) atom. The Tl(2)-O(1) bond length is 2.62 Å. The Tl(2)-O(13) bond length is 2.54 Å. The Tl(2)-O(2) bond length is 2.78 Å. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one W(1), one W(4), one Tl(1), and one Tl(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one W(2), one W(3), one Tl(1), and one Tl(2) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Mg(1), one W(2), and one W(3) atom. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Mg(1), one W(1), and one W(4) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Er(2), one W(3), and one Tl(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Er(1) and one W(4) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Mg(1), one Er(2), and one W(1) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Er(1) and one W(2) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Er(1), one W(1), and one W(2) atom. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Er(2), one W(1), and one W(2) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal non-coplanar geometry to one Er(1), one W(3), and one W(4) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Er(2), one W(3), and one W(4) atom. In the thirteenth O site, O(13) is bonded in a distorted T-shaped geometry to one Er(1), one W(1), and one Tl(2) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 150 degrees geometry to one Er(2) and one W(2) atom. In the fifteenth O site, O(15) is bonded in a distorted T-shaped geometry to one Mg(1), one Er(1), and one W(3) atom. In the sixteenth O site, O(16) is bonded in a bent 150 degrees geometry to one Er(2) and one W(4) atom.