MgFe(PO3)4 crystallizes in the monoclinic C2/c space group. Mg(1) is bonded to two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms to form MgO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with four equivalent P(2)O4 tetrahedra, and edges with two equivalent Fe(1)O6 octahedra. Fe(1) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms to form FeO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra, corners with four equivalent P(1)O4 tetrahedra, and edges with two equivalent Mg(1)O6 octahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 22-61°. In the second P site, P(2) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra, and corners with two equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-60°. There are six inequivalent O sites. In the first O site, O(3) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the second O site, O(4) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one P(1) atom. In the third O site, O(5) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(1), and one P(2) atom. In the fourth O site, O(6) is bonded in a bent 150 degrees geometry to one Mg(1) and one P(2) atom. In the fifth O site, O(1) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the sixth O site, O(2) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom.
MgFe(PO3)4 crystallizes in the monoclinic C2/c space group. Mg(1) is bonded to two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms to form MgO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with four equivalent P(2)O4 tetrahedra, and edges with two equivalent Fe(1)O6 octahedra. Both Mg(1)-O(4) bond lengths are 2.10 Å. Both Mg(1)-O(5) bond lengths are 2.12 Å. Both Mg(1)-O(6) bond lengths are 2.00 Å. Fe(1) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms to form FeO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra, corners with four equivalent P(1)O4 tetrahedra, and edges with two equivalent Mg(1)O6 octahedra. Both Fe(1)-O(3) bond lengths are 2.01 Å. Both Fe(1)-O(4) bond lengths are 2.16 Å. Both Fe(1)-O(5) bond lengths are 2.16 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(3), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 22-61°. The P(1)-O(1) bond length is 1.59 Å. The P(1)-O(2) bond length is 1.59 Å. The P(1)-O(3) bond length is 1.47 Å. The P(1)-O(4) bond length is 1.50 Å. In the second P site, P(2) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra, and corners with two equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-60°. The P(2)-O(1) bond length is 1.60 Å. The P(2)-O(2) bond length is 1.59 Å. The P(2)-O(5) bond length is 1.50 Å. The P(2)-O(6) bond length is 1.46 Å. There are six inequivalent O sites. In the first O site, O(3) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the second O site, O(4) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one P(1) atom. In the third O site, O(5) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(1), and one P(2) atom. In the fourth O site, O(6) is bonded in a bent 150 degrees geometry to one Mg(1) and one P(2) atom. In the fifth O site, O(1) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the sixth O site, O(2) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom.