MgFe2(PO5)2 crystallizes in the orthorhombic Fddd space group. Mg(1) is bonded in a distorted rectangular see-saw-like geometry to four equivalent O(3) atoms. Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with four equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. P(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-62°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to two equivalent Fe(1) atoms. 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(1) atom.
MgFe2(PO5)2 crystallizes in the orthorhombic Fddd space group. Mg(1) is bonded in a distorted rectangular see-saw-like geometry to four equivalent O(3) atoms. All Mg(1)-O(3) bond lengths are 2.19 Å. Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with four equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. Both Fe(1)-O(1) bond lengths are 1.94 Å. Both Fe(1)-O(2) bond lengths are 1.82 Å. Both Fe(1)-O(3) bond lengths are 2.17 Å. P(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-62°. Both P(1)-O(1) bond lengths are 1.55 Å. Both P(1)-O(3) bond lengths are 1.56 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to two equivalent Fe(1) atoms. 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(1) atom.