MgSb2(PO5)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(2), one O(6), one O(8), and one O(9) atom to form distorted MgO5 trigonal bipyramids that share  a cornercorner with one Sb(1)O6 octahedra,  a cornercorner with one Sb(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  an edgeedge with one Sb(1)O6 octahedra,  an edgeedge with one Sb(2)O6 octahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 42-68°. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to one O(2), one O(4), one O(5), one O(6), one O(7), and one O(9) atom to form SbO6 octahedra that share corners with two equivalent Sb(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 38-41°. In the second Sb site, Sb(2) is bonded to one O(1), one O(10), one O(3), one O(5), one O(6), and one O(8) atom to form distorted SbO6 octahedra that share corners with two equivalent Sb(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 38-41°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Sb(1)O6 octahedra, corners with two equivalent Sb(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 30-54°. In the second P site, P(2) is bonded to one O(10), one O(3), one O(4), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Sb(1)O6 octahedra, corners with two equivalent Sb(2)O6 octahedra, and  a cornercorner with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 25-43°. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1), one Sb(2), and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(1), one Sb(1), and one P(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Sb(2) and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Sb(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Sb(1) and one Sb(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(1), one Sb(1), and one Sb(2) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Sb(1) and one P(1) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Mg(1), one Sb(2), and one P(1) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Mg(1), one Sb(1), and one P(2) atom. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to one Sb(2) and one P(2) atom.
MgSb2(PO5)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(2), one O(6), one O(8), and one O(9) atom to form distorted MgO5 trigonal bipyramids that share  a cornercorner with one Sb(1)O6 octahedra,  a cornercorner with one Sb(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  an edgeedge with one Sb(1)O6 octahedra,  an edgeedge with one Sb(2)O6 octahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 42-68°. The Mg(1)-O(1) bond length is 2.06 Å. The Mg(1)-O(2) bond length is 2.22 Å. The Mg(1)-O(6) bond length is 1.98 Å. The Mg(1)-O(8) bond length is 2.05 Å. The Mg(1)-O(9) bond length is 2.13 Å. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to one O(2), one O(4), one O(5), one O(6), one O(7), and one O(9) atom to form SbO6 octahedra that share corners with two equivalent Sb(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 38-41°. The Sb(1)-O(2) bond length is 2.14 Å. The Sb(1)-O(4) bond length is 2.05 Å. The Sb(1)-O(5) bond length is 1.91 Å. The Sb(1)-O(6) bond length is 1.91 Å. The Sb(1)-O(7) bond length is 2.02 Å. The Sb(1)-O(9) bond length is 2.21 Å. In the second Sb site, Sb(2) is bonded to one O(1), one O(10), one O(3), one O(5), one O(6), and one O(8) atom to form distorted SbO6 octahedra that share corners with two equivalent Sb(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 38-41°. The Sb(2)-O(1) bond length is 2.64 Å. The Sb(2)-O(10) bond length is 2.10 Å. The Sb(2)-O(3) bond length is 2.11 Å. The Sb(2)-O(5) bond length is 2.01 Å. The Sb(2)-O(6) bond length is 2.56 Å. The Sb(2)-O(8) bond length is 2.65 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Sb(1)O6 octahedra, corners with two equivalent Sb(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 30-54°. The P(1)-O(1) bond length is 1.54 Å. The P(1)-O(2) bond length is 1.60 Å. The P(1)-O(7) bond length is 1.57 Å. The P(1)-O(8) bond length is 1.52 Å. In the second P site, P(2) is bonded to one O(10), one O(3), one O(4), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Sb(1)O6 octahedra, corners with two equivalent Sb(2)O6 octahedra, and  a cornercorner with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 25-43°. The P(2)-O(10) bond length is 1.55 Å. The P(2)-O(3) bond length is 1.53 Å. The P(2)-O(4) bond length is 1.55 Å. The P(2)-O(9) bond length is 1.58 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1), one Sb(2), and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(1), one Sb(1), and one P(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Sb(2) and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Sb(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Sb(1) and one Sb(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(1), one Sb(1), and one Sb(2) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Sb(1) and one P(1) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Mg(1), one Sb(2), and one P(1) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Mg(1), one Sb(1), and one P(2) atom. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to one Sb(2) and one P(2) atom.