MnFe(PO4)2 crystallizes in the orthorhombic Pmn2_1 space group. Mn(1) is bonded to one O(1), one O(2), and four equivalent O(3) atoms to form distorted MnO6 pentagonal pyramids that share corners with four equivalent Mn(1)O6 pentagonal pyramids,  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one P(1)O4 tetrahedra. Fe(1) is bonded to one O(4), one O(5), and four equivalent O(6) atoms to form distorted FeO6 octahedra that share corners with four equivalent Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(4), and two equivalent O(3) atoms to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with three equivalent Mn(1)O6 pentagonal pyramids, and  an edgeedge with one Mn(1)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles are 36°. In the second P site, P(2) is bonded to one O(1), one O(5), and two equivalent O(6) atoms to form PO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra,  a cornercorner with one Mn(1)O6 pentagonal pyramid, and  an edgeedge with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-56°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Mn(1) and one P(2) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Mn(1) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Mn(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Fe(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to two equivalent Fe(1) and one P(2) atom.
MnFe(PO4)2 crystallizes in the orthorhombic Pmn2_1 space group. Mn(1) is bonded to one O(1), one O(2), and four equivalent O(3) atoms to form distorted MnO6 pentagonal pyramids that share corners with four equivalent Mn(1)O6 pentagonal pyramids,  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one P(1)O4 tetrahedra. The Mn(1)-O(1) bond length is 1.92 Å. The Mn(1)-O(2) bond length is 1.91 Å. There are two shorter (2.00 Å) and two longer (2.35 Å) Mn(1)-O(3) bond lengths. Fe(1) is bonded to one O(4), one O(5), and four equivalent O(6) atoms to form distorted FeO6 octahedra that share corners with four equivalent Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. The Fe(1)-O(4) bond length is 1.92 Å. The Fe(1)-O(5) bond length is 1.94 Å. There are two shorter (2.11 Å) and two longer (2.17 Å) Fe(1)-O(6) bond lengths. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(4), and two equivalent O(3) atoms to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with three equivalent Mn(1)O6 pentagonal pyramids, and  an edgeedge with one Mn(1)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles are 36°. The P(1)-O(2) bond length is 1.54 Å. The P(1)-O(4) bond length is 1.53 Å. Both P(1)-O(3) bond lengths are 1.56 Å. In the second P site, P(2) is bonded to one O(1), one O(5), and two equivalent O(6) atoms to form PO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra,  a cornercorner with one Mn(1)O6 pentagonal pyramid, and  an edgeedge with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-56°. The P(2)-O(1) bond length is 1.53 Å. The P(2)-O(5) bond length is 1.52 Å. Both P(2)-O(6) bond lengths are 1.58 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Mn(1) and one P(2) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Mn(1) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Mn(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Fe(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to two equivalent Fe(1) and one P(2) atom.