Li2Fe(PO4)2 crystallizes in the monoclinic Cm space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form LiO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with two equivalent Fe(1)O6 octahedra. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(5), one O(6), and two equivalent O(1) atoms. Fe(1) is bonded to one O(2), one O(6), two equivalent O(1), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with two equivalent Li(1)O6 octahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form PO4 tetrahedra that share corners with three equivalent Li(1)O6 octahedra and corners with three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-56°. In the second P site, P(2) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with three equivalent Li(1)O6 octahedra and corners with three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-54°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Fe(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Li(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(2), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one P(2) atom.
Li2Fe(PO4)2 crystallizes in the monoclinic Cm space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form LiO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with two equivalent Fe(1)O6 octahedra. The Li(1)-O(3) bond length is 2.03 Å. The Li(1)-O(5) bond length is 2.10 Å. Both Li(1)-O(1) bond lengths are 2.33 Å. Both Li(1)-O(4) bond lengths are 2.20 Å. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(5), one O(6), and two equivalent O(1) atoms. The Li(2)-O(5) bond length is 1.96 Å. The Li(2)-O(6) bond length is 2.08 Å. Both Li(2)-O(1) bond lengths are 2.13 Å. Fe(1) is bonded to one O(2), one O(6), two equivalent O(1), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with two equivalent Li(1)O6 octahedra. The Fe(1)-O(2) bond length is 1.97 Å. The Fe(1)-O(6) bond length is 2.00 Å. Both Fe(1)-O(1) bond lengths are 2.11 Å. Both Fe(1)-O(4) bond lengths are 2.01 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form PO4 tetrahedra that share corners with three equivalent Li(1)O6 octahedra and corners with three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-56°. The P(1)-O(2) bond length is 1.54 Å. The P(1)-O(3) bond length is 1.53 Å. Both P(1)-O(1) bond lengths are 1.57 Å. In the second P site, P(2) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with three equivalent Li(1)O6 octahedra and corners with three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-54°. The P(2)-O(5) bond length is 1.55 Å. The P(2)-O(6) bond length is 1.56 Å. Both P(2)-O(4) bond lengths are 1.55 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Fe(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Li(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(2), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one P(2) atom.