Na2Fe3(PO4)3 is Esseneite-like structured and 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 two equivalent O(4), two equivalent O(6), and four equivalent O(5) atoms. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(3) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(4), one O(5), one O(6), and two equivalent O(1) atoms to form FeO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra, corners with four equivalent P(1)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, and  an edgeedge with one Fe(2)O6 octahedra. In the second Fe site, Fe(2) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(6) atoms to form distorted FeO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra, corners with four equivalent P(1)O4 tetrahedra, and edges with two equivalent Fe(1)O6 octahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form PO4 tetrahedra that share corners with two equivalent Fe(2)O6 octahedra and corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-57°. In the second P site, P(2) is bonded to two equivalent O(2) and two equivalent O(6) atoms to form PO4 tetrahedra that share corners with two equivalent Fe(2)O6 octahedra and corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-60°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Fe(1) and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(2), one Fe(1), and one P(2) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(2), one Fe(2), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one Fe(1), one Fe(2), and one P(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(1), one Fe(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(1), one Fe(1), one Fe(2), and one P(2) atom.
Na2Fe3(PO4)3 is Esseneite-like structured and 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 two equivalent O(4), two equivalent O(6), and four equivalent O(5) atoms. Both Na(1)-O(4) bond lengths are 2.86 Å. Both Na(1)-O(6) bond lengths are 2.88 Å. There are two shorter (2.41 Å) and two longer (2.59 Å) Na(1)-O(5) bond lengths. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(3) atoms. Both Na(2)-O(2) bond lengths are 2.35 Å. There are two shorter (2.46 Å) and two longer (2.57 Å) Na(2)-O(3) bond lengths. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(4), one O(5), one O(6), and two equivalent O(1) atoms to form FeO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra, corners with four equivalent P(1)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, and  an edgeedge with one Fe(2)O6 octahedra. The Fe(1)-O(2) bond length is 1.98 Å. The Fe(1)-O(4) bond length is 2.13 Å. The Fe(1)-O(5) bond length is 2.11 Å. The Fe(1)-O(6) bond length is 2.07 Å. There is one shorter (2.13 Å) and one longer (2.17 Å) Fe(1)-O(1) bond length. In the second Fe site, Fe(2) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(6) atoms to form distorted FeO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra, corners with four equivalent P(1)O4 tetrahedra, and edges with two equivalent Fe(1)O6 octahedra. Both Fe(2)-O(3) bond lengths are 2.16 Å. Both Fe(2)-O(4) bond lengths are 2.20 Å. Both Fe(2)-O(6) bond lengths are 2.25 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form PO4 tetrahedra that share corners with two equivalent Fe(2)O6 octahedra and corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-57°. The P(1)-O(1) bond length is 1.57 Å. The P(1)-O(3) bond length is 1.54 Å. The P(1)-O(4) bond length is 1.57 Å. The P(1)-O(5) bond length is 1.56 Å. In the second P site, P(2) is bonded to two equivalent O(2) and two equivalent O(6) atoms to form PO4 tetrahedra that share corners with two equivalent Fe(2)O6 octahedra and corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-60°. Both P(2)-O(2) bond lengths are 1.54 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 in a 3-coordinate geometry to two equivalent Fe(1) and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(2), one Fe(1), and one P(2) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(2), one Fe(2), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one Fe(1), one Fe(2), and one P(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(1), one Fe(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(1), one Fe(1), one Fe(2), and one P(2) atom.