MgAl2(PO5)2 crystallizes in the monoclinic P2_1/c space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(5) atoms to form distorted MgO6 octahedra that share corners with two equivalent Al(1)O6 octahedra, corners with four equivalent P(1)O4 tetrahedra, and faces with two equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles are 54°. Al(1) is bonded to one O(1), one O(2), one O(3), one O(4), and two equivalent O(5) atoms to form AlO6 octahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Al(1)O6 octahedra, corners with four equivalent P(1)O4 tetrahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-54°. 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 corners with two equivalent Mg(1)O6 octahedra and corners with four equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 30-49°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Mg(1), one Al(1), and one P(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Al(1) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Mg(1), one Al(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Al(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(1) and two equivalent Al(1) atoms.
MgAl2(PO5)2 crystallizes in the monoclinic P2_1/c space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(5) atoms to form distorted MgO6 octahedra that share corners with two equivalent Al(1)O6 octahedra, corners with four equivalent P(1)O4 tetrahedra, and faces with two equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles are 54°. Both Mg(1)-O(1) bond lengths are 2.03 Å. Both Mg(1)-O(3) bond lengths are 2.09 Å. Both Mg(1)-O(5) bond lengths are 2.07 Å. Al(1) is bonded to one O(1), one O(2), one O(3), one O(4), and two equivalent O(5) atoms to form AlO6 octahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Al(1)O6 octahedra, corners with four equivalent P(1)O4 tetrahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-54°. The Al(1)-O(1) bond length is 2.03 Å. The Al(1)-O(2) bond length is 1.85 Å. The Al(1)-O(3) bond length is 2.04 Å. The Al(1)-O(4) bond length is 1.82 Å. There is one shorter (1.87 Å) and one longer (1.91 Å) Al(1)-O(5) bond length. 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 corners with two equivalent Mg(1)O6 octahedra and corners with four equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 30-49°. The P(1)-O(1) bond length is 1.56 Å. The P(1)-O(2) bond length is 1.52 Å. The P(1)-O(3) bond length is 1.58 Å. The P(1)-O(4) bond length is 1.52 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Mg(1), one Al(1), and one P(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Al(1) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Mg(1), one Al(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Al(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(1) and two equivalent Al(1) atoms.