MgAg2(O4Br)2 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted MgO6 octahedra that share  an edgeedge with one Br(1)O4 tetrahedra. There are two inequivalent Ag sites. In the first Ag site, Ag(1) is bonded in a distorted see-saw-like geometry to two equivalent O(1) and two equivalent O(2) atoms. In the second Ag site, Ag(2) is bonded in a linear geometry to two equivalent O(2) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Ag(1) and one Br(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Ag(1), one Ag(2), and one Br(2) atom. In the third O site, O(3) is bonded in a water-like geometry to one Mg(1) and one Br(2) atom. In the fourth O site, O(4) is bonded in an L-shaped geometry to one Mg(1) and one Br(1) atom. There are two inequivalent Br sites. In the first Br site, Br(1) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form BrO4 tetrahedra that share  an edgeedge with one Mg(1)O6 octahedra. In the second Br site, Br(2) is bonded in a see-saw-like geometry to two equivalent O(2) and two equivalent O(3) atoms.
MgAg2(O4Br)2 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted MgO6 octahedra that share  an edgeedge with one Br(1)O4 tetrahedra. Both Mg(1)-O(2) bond lengths are 2.02 Å. Both Mg(1)-O(3) bond lengths are 2.17 Å. Both Mg(1)-O(4) bond lengths are 2.25 Å. There are two inequivalent Ag sites. In the first Ag site, Ag(1) is bonded in a distorted see-saw-like geometry to two equivalent O(1) and two equivalent O(2) atoms. Both Ag(1)-O(1) bond lengths are 2.44 Å. Both Ag(1)-O(2) bond lengths are 2.39 Å. In the second Ag site, Ag(2) is bonded in a linear geometry to two equivalent O(2) atoms. Both Ag(2)-O(2) bond lengths are 2.08 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Ag(1) and one Br(1) atom. The O(1)-Br(1) bond length is 1.68 Å. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Ag(1), one Ag(2), and one Br(2) atom. The O(2)-Br(2) bond length is 1.97 Å. In the third O site, O(3) is bonded in a water-like geometry to one Mg(1) and one Br(2) atom. The O(3)-Br(2) bond length is 1.70 Å. In the fourth O site, O(4) is bonded in an L-shaped geometry to one Mg(1) and one Br(1) atom. The O(4)-Br(1) bond length is 1.68 Å. There are two inequivalent Br sites. In the first Br site, Br(1) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form BrO4 tetrahedra that share  an edgeedge with one Mg(1)O6 octahedra. In the second Br site, Br(2) is bonded in a see-saw-like geometry to two equivalent O(2) and two equivalent O(3) atoms.