MgFe3(PO4)3 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(11), one O(3), one O(6), one O(8), and one O(9) atom to form distorted MgO5 trigonal bipyramids that share  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, corners with three equivalent Fe(1)O4 trigonal pyramids,  an edgeedge with one Fe(2)O4 tetrahedra, and  an edgeedge with one P(3)O4 tetrahedra. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(11), one O(6), and one O(9) atom to form FeO4 trigonal pyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and corners with three equivalent Mg(1)O5 trigonal bipyramids. In the second Fe site, Fe(2) is bonded to one O(12), one O(3), one O(4), and one O(8) atom to form distorted FeO4 tetrahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. In the third Fe site, Fe(3) is bonded to one O(10), one O(2), one O(5), and one O(7) atom to form FeO4 tetrahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with two equivalent P(2)O4 tetrahedra. There are three inequivalent P sites. In the first P site, P(1) is bonded to one O(12), one O(2), one O(4), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Fe(2)O4 tetrahedra and corners with two equivalent Fe(3)O4 tetrahedra. In the second P site, P(2) is bonded to one O(1), one O(10), one O(5), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Fe(3)O4 tetrahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid, and corners with two equivalent Fe(1)O4 trigonal pyramids. In the third P site, P(3) is bonded to one O(11), one O(3), one O(6), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Fe(2)O4 tetrahedra, corners with two equivalent Mg(1)O5 trigonal bipyramids, corners with two equivalent Fe(1)O4 trigonal pyramids, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Fe(1) and one P(2) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Fe(3) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one P(3) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one P(3) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(1) atom. In the eighth O site, O(8) is bonded in a T-shaped geometry to one Mg(1), one Fe(2), and one P(3) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Mg(1), one Fe(1), and one P(2) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(2) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one P(3) atom. In the twelfth O site, O(12) is bonded in a bent 120 degrees geometry to one Fe(2) and one P(1) atom.
MgFe3(PO4)3 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(11), one O(3), one O(6), one O(8), and one O(9) atom to form distorted MgO5 trigonal bipyramids that share  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, corners with three equivalent Fe(1)O4 trigonal pyramids,  an edgeedge with one Fe(2)O4 tetrahedra, and  an edgeedge with one P(3)O4 tetrahedra. The Mg(1)-O(11) bond length is 2.14 Å. The Mg(1)-O(3) bond length is 2.05 Å. The Mg(1)-O(6) bond length is 2.00 Å. The Mg(1)-O(8) bond length is 2.11 Å. The Mg(1)-O(9) bond length is 2.08 Å. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(11), one O(6), and one O(9) atom to form FeO4 trigonal pyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and corners with three equivalent Mg(1)O5 trigonal bipyramids. The Fe(1)-O(1) bond length is 1.95 Å. The Fe(1)-O(11) bond length is 2.03 Å. The Fe(1)-O(6) bond length is 2.18 Å. The Fe(1)-O(9) bond length is 2.05 Å. In the second Fe site, Fe(2) is bonded to one O(12), one O(3), one O(4), and one O(8) atom to form distorted FeO4 tetrahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The Fe(2)-O(12) bond length is 1.95 Å. The Fe(2)-O(3) bond length is 2.19 Å. The Fe(2)-O(4) bond length is 1.92 Å. The Fe(2)-O(8) bond length is 2.11 Å. In the third Fe site, Fe(3) is bonded to one O(10), one O(2), one O(5), and one O(7) atom to form FeO4 tetrahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with two equivalent P(2)O4 tetrahedra. The Fe(3)-O(10) bond length is 1.92 Å. The Fe(3)-O(2) bond length is 1.88 Å. The Fe(3)-O(5) bond length is 1.93 Å. The Fe(3)-O(7) bond length is 1.86 Å. There are three inequivalent P sites. In the first P site, P(1) is bonded to one O(12), one O(2), one O(4), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Fe(2)O4 tetrahedra and corners with two equivalent Fe(3)O4 tetrahedra. The P(1)-O(12) bond length is 1.54 Å. The P(1)-O(2) bond length is 1.56 Å. The P(1)-O(4) bond length is 1.53 Å. The P(1)-O(7) bond length is 1.56 Å. In the second P site, P(2) is bonded to one O(1), one O(10), one O(5), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Fe(3)O4 tetrahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid, and corners with two equivalent Fe(1)O4 trigonal pyramids. The P(2)-O(1) bond length is 1.54 Å. The P(2)-O(10) bond length is 1.54 Å. The P(2)-O(5) bond length is 1.55 Å. The P(2)-O(9) bond length is 1.59 Å. In the third P site, P(3) is bonded to one O(11), one O(3), one O(6), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Fe(2)O4 tetrahedra, corners with two equivalent Mg(1)O5 trigonal bipyramids, corners with two equivalent Fe(1)O4 trigonal pyramids, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The P(3)-O(11) bond length is 1.58 Å. The P(3)-O(3) bond length is 1.54 Å. The P(3)-O(6) bond length is 1.56 Å. The P(3)-O(8) bond length is 1.54 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Fe(1) and one P(2) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Fe(3) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one P(3) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one P(3) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(1) atom. In the eighth O site, O(8) is bonded in a T-shaped geometry to one Mg(1), one Fe(2), and one P(3) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Mg(1), one Fe(1), and one P(2) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(2) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one P(3) atom. In the twelfth O site, O(12) is bonded in a bent 120 degrees geometry to one Fe(2) and one P(1) atom.