MgEu2Ag2(WO4)4 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form MgO6 octahedra that share edges with two equivalent W(1)O6 octahedra and edges with two equivalent W(2)O6 octahedra. Eu(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(6), and two equivalent O(8) atoms. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(1), one O(2), one O(5), one O(6), one O(7), and one O(8) atom to form distorted WO6 octahedra that share  an edgeedge with one Mg(1)O6 octahedra and edges with two equivalent W(2)O6 octahedra. In the second W site, W(2) is bonded to one O(1), one O(2), one O(3), one O(4), and two equivalent O(7) atoms to form distorted WO6 octahedra that share  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one W(2)O6 octahedra, and edges with two equivalent W(1)O6 octahedra. Ag(1) is bonded in a 4-coordinate geometry to one O(3), one O(5), one O(7), and one O(8) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mg(1), one Eu(1), one W(1), and one W(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Eu(1), one W(1), and one W(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Eu(1), one W(2), and one Ag(1) atom. In the fourth O site, O(4) is bonded in a T-shaped geometry to one Mg(1), one Eu(1), and one W(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Mg(1), one W(1), and one Ag(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Eu(1) and one W(1) atom. In the seventh O site, O(7) is bonded to one W(1), two equivalent W(2), and one Ag(1) atom to form OAgW3 tetrahedra that share corners with two equivalent O(8)Eu2AgW tetrahedra and  an edgeedge with one O(7)AgW3 tetrahedra. In the eighth O site, O(8) is bonded to two equivalent Eu(1), one W(1), and one Ag(1) atom to form distorted OEu2AgW tetrahedra that share corners with two equivalent O(7)AgW3 tetrahedra and  an edgeedge with one O(8)Eu2AgW tetrahedra.
MgEu2Ag2(WO4)4 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form MgO6 octahedra that share edges with two equivalent W(1)O6 octahedra and edges with two equivalent W(2)O6 octahedra. Both Mg(1)-O(1) bond lengths are 2.12 Å. Both Mg(1)-O(4) bond lengths are 2.11 Å. Both Mg(1)-O(5) bond lengths are 2.05 Å. Eu(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(6), and two equivalent O(8) atoms. The Eu(1)-O(1) bond length is 2.59 Å. The Eu(1)-O(2) bond length is 2.43 Å. The Eu(1)-O(3) bond length is 2.47 Å. The Eu(1)-O(4) bond length is 2.54 Å. The Eu(1)-O(6) bond length is 2.40 Å. There is one shorter (2.63 Å) and one longer (2.68 Å) Eu(1)-O(8) bond length. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(1), one O(2), one O(5), one O(6), one O(7), and one O(8) atom to form distorted WO6 octahedra that share  an edgeedge with one Mg(1)O6 octahedra and edges with two equivalent W(2)O6 octahedra. The W(1)-O(1) bond length is 2.22 Å. The W(1)-O(2) bond length is 2.14 Å. The W(1)-O(5) bond length is 1.85 Å. The W(1)-O(6) bond length is 1.80 Å. The W(1)-O(7) bond length is 2.12 Å. The W(1)-O(8) bond length is 1.86 Å. In the second W site, W(2) is bonded to one O(1), one O(2), one O(3), one O(4), and two equivalent O(7) atoms to form distorted WO6 octahedra that share  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one W(2)O6 octahedra, and edges with two equivalent W(1)O6 octahedra. The W(2)-O(1) bond length is 2.02 Å. The W(2)-O(2) bond length is 1.95 Å. The W(2)-O(3) bond length is 1.81 Å. The W(2)-O(4) bond length is 1.85 Å. There is one shorter (2.16 Å) and one longer (2.17 Å) W(2)-O(7) bond length. Ag(1) is bonded in a 4-coordinate geometry to one O(3), one O(5), one O(7), and one O(8) atom. The Ag(1)-O(3) bond length is 2.55 Å. The Ag(1)-O(5) bond length is 2.30 Å. The Ag(1)-O(7) bond length is 2.62 Å. The Ag(1)-O(8) bond length is 2.47 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mg(1), one Eu(1), one W(1), and one W(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Eu(1), one W(1), and one W(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Eu(1), one W(2), and one Ag(1) atom. In the fourth O site, O(4) is bonded in a T-shaped geometry to one Mg(1), one Eu(1), and one W(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Mg(1), one W(1), and one Ag(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Eu(1) and one W(1) atom. In the seventh O site, O(7) is bonded to one W(1), two equivalent W(2), and one Ag(1) atom to form OAgW3 tetrahedra that share corners with two equivalent O(8)Eu2AgW tetrahedra and  an edgeedge with one O(7)AgW3 tetrahedra. In the eighth O site, O(8) is bonded to two equivalent Eu(1), one W(1), and one Ag(1) atom to form distorted OEu2AgW tetrahedra that share corners with two equivalent O(7)AgW3 tetrahedra and  an edgeedge with one O(8)Eu2AgW tetrahedra.