MgAg3(AsO4)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(2), one O(4), one O(5), and one O(8) atom to form distorted MgO5 trigonal bipyramids that share  a cornercorner with one As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra, corners with two equivalent Ag(2)O5 trigonal bipyramids, and  an edgeedge with one As(1)O4 tetrahedra. There are three inequivalent Ag sites. In the first Ag site, Ag(1) is bonded in a 4-coordinate geometry to one O(1), one O(4), one O(6), and one O(8) atom. In the second Ag site, Ag(2) is bonded to one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form distorted AgO5 trigonal bipyramids that share  a cornercorner with one As(2)O4 tetrahedra, corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent Mg(1)O5 trigonal bipyramids, and  an edgeedge with one As(2)O4 tetrahedra. In the third Ag site, Ag(3) is bonded in a distorted see-saw-like geometry to one O(1), one O(3), one O(6), and one O(7) atom. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form AsO4 tetrahedra that share  a cornercorner with one Mg(1)O5 trigonal bipyramid, corners with two equivalent Ag(2)O5 trigonal bipyramids, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. In the second As site, As(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form AsO4 tetrahedra that share  a cornercorner with one Ag(2)O5 trigonal bipyramid, corners with two equivalent Mg(1)O5 trigonal bipyramids, and  an edgeedge with one Ag(2)O5 trigonal bipyramid. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Ag(1), one Ag(3), and one As(1) atom to form OMgAg2As trigonal pyramids that share  a cornercorner with one O(8)MgAg2As tetrahedra, corners with two equivalent O(6)Ag3As tetrahedra, and  an edgeedge with one O(8)MgAg2As tetrahedra. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Mg(1) and one As(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ag(2), one Ag(3), and one As(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Mg(1), one Ag(1), and one As(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Mg(1), one Ag(2), and one As(2) atom. In the sixth O site, O(6) is bonded to one Ag(1), one Ag(2), one Ag(3), and one As(2) atom to form corner-sharing OAg3As tetrahedra. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Ag(2), one Ag(3), and one As(1) atom. In the eighth O site, O(8) is bonded to one Mg(1), one Ag(1), one Ag(2), and one As(1) atom to form distorted OMgAg2As tetrahedra that share corners with two equivalent O(6)Ag3As tetrahedra,  a cornercorner with one O(1)MgAg2As trigonal pyramid, and  an edgeedge with one O(1)MgAg2As trigonal pyramid.
MgAg3(AsO4)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(2), one O(4), one O(5), and one O(8) atom to form distorted MgO5 trigonal bipyramids that share  a cornercorner with one As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra, corners with two equivalent Ag(2)O5 trigonal bipyramids, and  an edgeedge with one As(1)O4 tetrahedra. The Mg(1)-O(1) bond length is 2.22 Å. The Mg(1)-O(2) bond length is 2.01 Å. The Mg(1)-O(4) bond length is 2.03 Å. The Mg(1)-O(5) bond length is 2.09 Å. The Mg(1)-O(8) bond length is 2.18 Å. There are three inequivalent Ag sites. In the first Ag site, Ag(1) is bonded in a 4-coordinate geometry to one O(1), one O(4), one O(6), and one O(8) atom. The Ag(1)-O(1) bond length is 2.24 Å. The Ag(1)-O(4) bond length is 2.55 Å. The Ag(1)-O(6) bond length is 2.46 Å. The Ag(1)-O(8) bond length is 2.31 Å. In the second Ag site, Ag(2) is bonded to one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form distorted AgO5 trigonal bipyramids that share  a cornercorner with one As(2)O4 tetrahedra, corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent Mg(1)O5 trigonal bipyramids, and  an edgeedge with one As(2)O4 tetrahedra. The Ag(2)-O(3) bond length is 2.62 Å. The Ag(2)-O(5) bond length is 2.25 Å. The Ag(2)-O(6) bond length is 2.18 Å. The Ag(2)-O(7) bond length is 2.42 Å. The Ag(2)-O(8) bond length is 2.30 Å. In the third Ag site, Ag(3) is bonded in a distorted see-saw-like geometry to one O(1), one O(3), one O(6), and one O(7) atom. The Ag(3)-O(1) bond length is 2.44 Å. The Ag(3)-O(3) bond length is 2.33 Å. The Ag(3)-O(6) bond length is 2.46 Å. The Ag(3)-O(7) bond length is 2.40 Å. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form AsO4 tetrahedra that share  a cornercorner with one Mg(1)O5 trigonal bipyramid, corners with two equivalent Ag(2)O5 trigonal bipyramids, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The As(1)-O(1) bond length is 1.76 Å. The As(1)-O(2) bond length is 1.70 Å. The As(1)-O(7) bond length is 1.71 Å. The As(1)-O(8) bond length is 1.78 Å. In the second As site, As(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form AsO4 tetrahedra that share  a cornercorner with one Ag(2)O5 trigonal bipyramid, corners with two equivalent Mg(1)O5 trigonal bipyramids, and  an edgeedge with one Ag(2)O5 trigonal bipyramid. The As(2)-O(3) bond length is 1.70 Å. The As(2)-O(4) bond length is 1.72 Å. The As(2)-O(5) bond length is 1.76 Å. The As(2)-O(6) bond length is 1.76 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Ag(1), one Ag(3), and one As(1) atom to form OMgAg2As trigonal pyramids that share  a cornercorner with one O(8)MgAg2As tetrahedra, corners with two equivalent O(6)Ag3As tetrahedra, and  an edgeedge with one O(8)MgAg2As tetrahedra. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Mg(1) and one As(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ag(2), one Ag(3), and one As(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Mg(1), one Ag(1), and one As(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Mg(1), one Ag(2), and one As(2) atom. In the sixth O site, O(6) is bonded to one Ag(1), one Ag(2), one Ag(3), and one As(2) atom to form corner-sharing OAg3As tetrahedra. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Ag(2), one Ag(3), and one As(1) atom. In the eighth O site, O(8) is bonded to one Mg(1), one Ag(1), one Ag(2), and one As(1) atom to form distorted OMgAg2As tetrahedra that share corners with two equivalent O(6)Ag3As tetrahedra,  a cornercorner with one O(1)MgAg2As trigonal pyramid, and  an edgeedge with one O(1)MgAg2As trigonal pyramid.