Na3Fe2(PO4)3 crystallizes in the monoclinic C2/c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(4), one O(5), two equivalent O(1), and two equivalent O(6) atoms. In the second Na site, Na(2) is bonded in a distorted hexagonal planar geometry to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms. Fe(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form FeO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra and corners with four equivalent P(1)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form PO4 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 16-42°. In the second P site, P(2) is bonded to two equivalent O(4) and two equivalent O(6) atoms to form PO4 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 29-35°. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), two equivalent Na(1), one Fe(1), and one P(1) atom to form distorted corner-sharing ONa3FeP trigonal bipyramids. In the second O site, O(2) is bonded in a distorted linear geometry to one Na(1), one Fe(1), and one P(1) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Fe(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Fe(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(1), one Fe(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to two equivalent Na(1), one Fe(1), and one P(2) atom.
Na3Fe2(PO4)3 crystallizes in the monoclinic C2/c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(4), one O(5), two equivalent O(1), and two equivalent O(6) atoms. The Na(1)-O(2) bond length is 2.88 Å. The Na(1)-O(3) bond length is 2.45 Å. The Na(1)-O(4) bond length is 2.40 Å. The Na(1)-O(5) bond length is 2.46 Å. There is one shorter (2.43 Å) and one longer (2.49 Å) Na(1)-O(1) bond length. There is one shorter (2.55 Å) and one longer (2.92 Å) Na(1)-O(6) bond length. In the second Na site, Na(2) is bonded in a distorted hexagonal planar geometry to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms. Both Na(2)-O(1) bond lengths are 2.46 Å. Both Na(2)-O(3) bond lengths are 2.41 Å. Both Na(2)-O(4) bond lengths are 2.47 Å. Fe(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form FeO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra and corners with four equivalent P(1)O4 tetrahedra. The Fe(1)-O(1) bond length is 2.12 Å. The Fe(1)-O(2) bond length is 1.93 Å. The Fe(1)-O(3) bond length is 2.05 Å. The Fe(1)-O(4) bond length is 2.08 Å. The Fe(1)-O(5) bond length is 2.01 Å. The Fe(1)-O(6) bond length is 2.03 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form PO4 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 16-42°. The P(1)-O(1) bond length is 1.57 Å. The P(1)-O(2) bond length is 1.54 Å. The P(1)-O(3) bond length is 1.55 Å. The P(1)-O(5) bond length is 1.55 Å. In the second P site, P(2) is bonded to two equivalent O(4) and two equivalent O(6) atoms to form PO4 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 29-35°. Both P(2)-O(4) bond lengths are 1.55 Å. Both P(2)-O(6) bond lengths are 1.56 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), two equivalent Na(1), one Fe(1), and one P(1) atom to form distorted corner-sharing ONa3FeP trigonal bipyramids. In the second O site, O(2) is bonded in a distorted linear geometry to one Na(1), one Fe(1), and one P(1) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Fe(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Fe(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(1), one Fe(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to two equivalent Na(1), one Fe(1), and one P(2) atom.