Na2FeCPO7 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(4), one O(6), one O(7), one O(9), and two equivalent O(1) atoms. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(10), one O(3), one O(5), one O(8), and two equivalent O(2) atoms. In the third Na site, Na(3) is bonded in a 7-coordinate geometry to one O(1), one O(11), one O(13), one O(3), one O(5), and two equivalent O(9) atoms. In the fourth Na site, Na(4) is bonded in a 7-coordinate geometry to one O(12), one O(14), one O(2), one O(4), one O(6), and two equivalent O(10) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(11), one O(14), one O(3), one O(5), one O(7), and one O(9) atom to form FeO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with two equivalent P(2)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to one O(10), one O(12), one O(13), one O(4), one O(6), and one O(8) atom to form FeO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with two equivalent P(2)O4 tetrahedra. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one O(2), one O(3), and one O(5) atom. In the second C site, C(2) is bonded in a trigonal planar geometry to one O(1), one O(4), and one O(6) atom. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(12), one O(13), one O(7), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 32-43°. In the second P site, P(2) is bonded to one O(10), one O(11), one O(14), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 33-43°. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(3), two equivalent Na(1), and one C(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(4), two equivalent Na(2), and one C(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(2), one Na(3), one Fe(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), one Na(4), one Fe(2), and one C(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(2), one Na(3), one Fe(1), and one C(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(1), one Na(4), one Fe(2), and one C(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(1), one Fe(1), and one P(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(2), one Fe(2), and one P(2) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Na(1), two equivalent Na(3), one Fe(1), and one P(1) atom. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to one Na(2), two equivalent Na(4), one Fe(2), and one P(2) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Na(3), one Fe(1), and one P(2) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Na(4), one Fe(2), and one P(1) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Na(3), one Fe(2), and one P(1) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Na(4), one Fe(1), and one P(2) atom.
Na2FeCPO7 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(4), one O(6), one O(7), one O(9), and two equivalent O(1) atoms. The Na(1)-O(4) bond length is 2.35 Å. The Na(1)-O(6) bond length is 2.77 Å. The Na(1)-O(7) bond length is 2.43 Å. The Na(1)-O(9) bond length is 2.57 Å. There is one shorter (2.41 Å) and one longer (2.90 Å) Na(1)-O(1) bond length. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(10), one O(3), one O(5), one O(8), and two equivalent O(2) atoms. The Na(2)-O(10) bond length is 2.59 Å. The Na(2)-O(3) bond length is 2.36 Å. The Na(2)-O(5) bond length is 2.75 Å. The Na(2)-O(8) bond length is 2.44 Å. There is one shorter (2.41 Å) and one longer (2.90 Å) Na(2)-O(2) bond length. In the third Na site, Na(3) is bonded in a 7-coordinate geometry to one O(1), one O(11), one O(13), one O(3), one O(5), and two equivalent O(9) atoms. The Na(3)-O(1) bond length is 2.26 Å. The Na(3)-O(11) bond length is 2.36 Å. The Na(3)-O(13) bond length is 2.51 Å. The Na(3)-O(3) bond length is 2.72 Å. The Na(3)-O(5) bond length is 2.41 Å. There is one shorter (2.50 Å) and one longer (2.91 Å) Na(3)-O(9) bond length. In the fourth Na site, Na(4) is bonded in a 7-coordinate geometry to one O(12), one O(14), one O(2), one O(4), one O(6), and two equivalent O(10) atoms. The Na(4)-O(12) bond length is 2.37 Å. The Na(4)-O(14) bond length is 2.52 Å. The Na(4)-O(2) bond length is 2.26 Å. The Na(4)-O(4) bond length is 2.73 Å. The Na(4)-O(6) bond length is 2.40 Å. There is one shorter (2.50 Å) and one longer (2.92 Å) Na(4)-O(10) bond length. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(11), one O(14), one O(3), one O(5), one O(7), and one O(9) atom to form FeO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with two equivalent P(2)O4 tetrahedra. The Fe(1)-O(11) bond length is 1.98 Å. The Fe(1)-O(14) bond length is 1.97 Å. The Fe(1)-O(3) bond length is 2.13 Å. The Fe(1)-O(5) bond length is 2.12 Å. The Fe(1)-O(7) bond length is 1.99 Å. The Fe(1)-O(9) bond length is 2.10 Å. In the second Fe site, Fe(2) is bonded to one O(10), one O(12), one O(13), one O(4), one O(6), and one O(8) atom to form FeO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with two equivalent P(2)O4 tetrahedra. The Fe(2)-O(10) bond length is 2.10 Å. The Fe(2)-O(12) bond length is 1.98 Å. The Fe(2)-O(13) bond length is 1.97 Å. The Fe(2)-O(4) bond length is 2.14 Å. The Fe(2)-O(6) bond length is 2.11 Å. The Fe(2)-O(8) bond length is 2.00 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one O(2), one O(3), and one O(5) atom. The C(1)-O(2) bond length is 1.27 Å. The C(1)-O(3) bond length is 1.32 Å. The C(1)-O(5) bond length is 1.31 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one O(1), one O(4), and one O(6) atom. The C(2)-O(1) bond length is 1.27 Å. The C(2)-O(4) bond length is 1.32 Å. The C(2)-O(6) bond length is 1.31 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(12), one O(13), one O(7), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 32-43°. The P(1)-O(12) bond length is 1.54 Å. The P(1)-O(13) bond length is 1.56 Å. The P(1)-O(7) bond length is 1.55 Å. The P(1)-O(9) bond length is 1.55 Å. In the second P site, P(2) is bonded to one O(10), one O(11), one O(14), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 33-43°. The P(2)-O(10) bond length is 1.55 Å. The P(2)-O(11) bond length is 1.54 Å. The P(2)-O(14) bond length is 1.56 Å. The P(2)-O(8) bond length is 1.55 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(3), two equivalent Na(1), and one C(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(4), two equivalent Na(2), and one C(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(2), one Na(3), one Fe(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), one Na(4), one Fe(2), and one C(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(2), one Na(3), one Fe(1), and one C(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(1), one Na(4), one Fe(2), and one C(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(1), one Fe(1), and one P(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(2), one Fe(2), and one P(2) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Na(1), two equivalent Na(3), one Fe(1), and one P(1) atom. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to one Na(2), two equivalent Na(4), one Fe(2), and one P(2) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Na(3), one Fe(1), and one P(2) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Na(4), one Fe(2), and one P(1) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Na(3), one Fe(2), and one P(1) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Na(4), one Fe(1), and one P(2) atom.