Mg2FeAl4(PO6)4 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to one O(10), one O(3), one O(6), one O(7), one O(8), and one O(9) atom to form MgO6 octahedra that share corners with two equivalent Al(2)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, and  a faceface with one Al(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-54°. Fe(1) is bonded to two equivalent O(11), two equivalent O(3), and two equivalent O(9) atoms to form FeO6 octahedra that share corners with two equivalent Al(1)O6 octahedra, corners with four equivalent P(2)O4 tetrahedra, and edges with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 46°. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent O(11), two equivalent O(12), and two equivalent O(5) atoms to form AlO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Al(2)O6 octahedra, and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 36-46°. In the second Al site, Al(2) is bonded to one O(1), one O(12), one O(2), one O(4), one O(7), and one O(8) atom to form AlO6 octahedra that share  a cornercorner with one Al(1)O6 octahedra,  a cornercorner with one Al(3)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and corners with two equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 36-54°. In the third Al site, Al(3) is bonded to two equivalent O(10), two equivalent O(6), and two equivalent O(8) atoms to form AlO6 octahedra that share corners with two equivalent Al(2)O6 octahedra, corners with four equivalent P(1)O4 tetrahedra, and faces with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 44°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(10), one O(2), and one O(6) atom to form PO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Al(2)O6 octahedra, and corners with two equivalent Al(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 37-52°. In the second P site, P(2) is bonded to one O(3), one O(4), one O(5), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Al(1)O6 octahedra,  a cornercorner with one Al(2)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra, and corners with two equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-57°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Al(2) and one P(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Al(2) and one P(1) atom. In the third O site, O(3) 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(4) is bonded in a bent 120 degrees geometry to one Al(2) and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Al(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(1), one Al(3), and one P(1) atom. In the seventh O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Mg(1) and one Al(2) atom. In the eighth O site, O(8) is bonded in a distorted T-shaped geometry to one Mg(1), one Al(2), and one Al(3) atom. In the ninth O site, O(9) is bonded in a distorted 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 3-coordinate geometry to one Mg(1), one Al(3), and one P(1) atom. In the eleventh O site, O(11) is bonded in a distorted bent 120 degrees geometry to one Fe(1) and one Al(1) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Al(1) and one Al(2) atom.
Mg2FeAl4(PO6)4 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to one O(10), one O(3), one O(6), one O(7), one O(8), and one O(9) atom to form MgO6 octahedra that share corners with two equivalent Al(2)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, and  a faceface with one Al(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-54°. The Mg(1)-O(10) bond length is 2.22 Å. The Mg(1)-O(3) bond length is 2.08 Å. The Mg(1)-O(6) bond length is 2.12 Å. The Mg(1)-O(7) bond length is 2.10 Å. The Mg(1)-O(8) bond length is 2.15 Å. The Mg(1)-O(9) bond length is 2.10 Å. Fe(1) is bonded to two equivalent O(11), two equivalent O(3), and two equivalent O(9) atoms to form FeO6 octahedra that share corners with two equivalent Al(1)O6 octahedra, corners with four equivalent P(2)O4 tetrahedra, and edges with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 46°. Both Fe(1)-O(11) bond lengths are 2.04 Å. Both Fe(1)-O(3) bond lengths are 2.07 Å. Both Fe(1)-O(9) bond lengths are 2.01 Å. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent O(11), two equivalent O(12), and two equivalent O(5) atoms to form AlO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Al(2)O6 octahedra, and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 36-46°. Both Al(1)-O(11) bond lengths are 1.90 Å. Both Al(1)-O(12) bond lengths are 1.88 Å. Both Al(1)-O(5) bond lengths are 1.88 Å. In the second Al site, Al(2) is bonded to one O(1), one O(12), one O(2), one O(4), one O(7), and one O(8) atom to form AlO6 octahedra that share  a cornercorner with one Al(1)O6 octahedra,  a cornercorner with one Al(3)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and corners with two equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 36-54°. The Al(2)-O(1) bond length is 1.88 Å. The Al(2)-O(12) bond length is 1.89 Å. The Al(2)-O(2) bond length is 1.84 Å. The Al(2)-O(4) bond length is 1.89 Å. The Al(2)-O(7) bond length is 1.95 Å. The Al(2)-O(8) bond length is 1.89 Å. In the third Al site, Al(3) is bonded to two equivalent O(10), two equivalent O(6), and two equivalent O(8) atoms to form AlO6 octahedra that share corners with two equivalent Al(2)O6 octahedra, corners with four equivalent P(1)O4 tetrahedra, and faces with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 44°. Both Al(3)-O(10) bond lengths are 1.98 Å. Both Al(3)-O(6) bond lengths are 1.91 Å. Both Al(3)-O(8) bond lengths are 1.89 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(10), one O(2), and one O(6) atom to form PO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Al(2)O6 octahedra, and corners with two equivalent Al(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 37-52°. The P(1)-O(1) bond length is 1.54 Å. The P(1)-O(10) bond length is 1.57 Å. The P(1)-O(2) bond length is 1.52 Å. The P(1)-O(6) bond length is 1.57 Å. In the second P site, P(2) is bonded to one O(3), one O(4), one O(5), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Al(1)O6 octahedra,  a cornercorner with one Al(2)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra, and corners with two equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-57°. The P(2)-O(3) bond length is 1.56 Å. The P(2)-O(4) bond length is 1.54 Å. The P(2)-O(5) bond length is 1.53 Å. The P(2)-O(9) bond length is 1.55 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Al(2) and one P(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Al(2) and one P(1) atom. In the third O site, O(3) 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(4) is bonded in a bent 120 degrees geometry to one Al(2) and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Al(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(1), one Al(3), and one P(1) atom. In the seventh O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Mg(1) and one Al(2) atom. In the eighth O site, O(8) is bonded in a distorted T-shaped geometry to one Mg(1), one Al(2), and one Al(3) atom. In the ninth O site, O(9) is bonded in a distorted 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 3-coordinate geometry to one Mg(1), one Al(3), and one P(1) atom. In the eleventh O site, O(11) is bonded in a distorted bent 120 degrees geometry to one Fe(1) and one Al(1) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Al(1) and one Al(2) atom.