MgMo2(PO5)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(10), one O(2), one O(5), one O(7), and one O(9) atom to form distorted MgO5 trigonal bipyramids that share  a cornercorner with one Mo(1)O6 octahedra,  a cornercorner with one Mo(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  an edgeedge with one Mo(1)O6 octahedra,  an edgeedge with one Mo(2)O6 octahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-59°. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(1), one O(10), one O(2), one O(3), one O(6), and one O(7) atom to form MoO6 octahedra that share corners with two equivalent Mo(2)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 29-45°. In the second Mo site, Mo(2) is bonded to one O(1), one O(2), one O(4), one O(5), one O(8), and one O(9) atom to form MoO6 octahedra that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 29-45°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(3), one O(5), one O(7), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent Mo(2)O6 octahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 29-51°. In the second P site, P(2) is bonded to one O(10), one O(4), one O(6), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent Mo(2)O6 octahedra, and  a cornercorner with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 21-47°. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Mo(1) and one Mo(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mo(1), and one Mo(2) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Mo(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Mo(2) and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(1), one Mo(2), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Mo(1) and one P(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Mg(1), one Mo(1), and one P(1) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Mo(2) and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mo(2), and one P(1) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Mg(1), one Mo(1), and one P(2) atom.
MgMo2(PO5)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(10), one O(2), one O(5), one O(7), and one O(9) atom to form distorted MgO5 trigonal bipyramids that share  a cornercorner with one Mo(1)O6 octahedra,  a cornercorner with one Mo(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  an edgeedge with one Mo(1)O6 octahedra,  an edgeedge with one Mo(2)O6 octahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-59°. The Mg(1)-O(10) bond length is 2.12 Å. The Mg(1)-O(2) bond length is 1.97 Å. The Mg(1)-O(5) bond length is 2.12 Å. The Mg(1)-O(7) bond length is 2.12 Å. The Mg(1)-O(9) bond length is 2.15 Å. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(1), one O(10), one O(2), one O(3), one O(6), and one O(7) atom to form MoO6 octahedra that share corners with two equivalent Mo(2)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 29-45°. The Mo(1)-O(1) bond length is 1.89 Å. The Mo(1)-O(10) bond length is 2.19 Å. The Mo(1)-O(2) bond length is 2.04 Å. The Mo(1)-O(3) bond length is 2.05 Å. The Mo(1)-O(6) bond length is 2.07 Å. The Mo(1)-O(7) bond length is 2.21 Å. In the second Mo site, Mo(2) is bonded to one O(1), one O(2), one O(4), one O(5), one O(8), and one O(9) atom to form MoO6 octahedra that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 29-45°. The Mo(2)-O(1) bond length is 1.91 Å. The Mo(2)-O(2) bond length is 2.01 Å. The Mo(2)-O(4) bond length is 2.09 Å. The Mo(2)-O(5) bond length is 2.16 Å. The Mo(2)-O(8) bond length is 2.01 Å. The Mo(2)-O(9) bond length is 2.21 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(3), one O(5), one O(7), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent Mo(2)O6 octahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 29-51°. The P(1)-O(3) bond length is 1.53 Å. The P(1)-O(5) bond length is 1.56 Å. The P(1)-O(7) bond length is 1.57 Å. The P(1)-O(9) bond length is 1.56 Å. In the second P site, P(2) is bonded to one O(10), one O(4), one O(6), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent Mo(2)O6 octahedra, and  a cornercorner with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 21-47°. The P(2)-O(10) bond length is 1.59 Å. The P(2)-O(4) bond length is 1.55 Å. The P(2)-O(6) bond length is 1.54 Å. The P(2)-O(8) bond length is 1.53 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Mo(1) and one Mo(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mo(1), and one Mo(2) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Mo(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Mo(2) and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(1), one Mo(2), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Mo(1) and one P(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Mg(1), one Mo(1), and one P(1) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Mo(2) and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mo(2), and one P(1) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Mg(1), one Mo(1), and one P(2) atom.