Na2FeCAsO7 crystallizes in the monoclinic P2_1/m space group. Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. Fe(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(6) atoms to form distorted FeO6 octahedra that share corners with four equivalent As(1)O4 tetrahedra. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. As(1) is bonded to one O(4), one O(5), and two equivalent O(6) atoms to form AsO4 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-54°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Na(1) and one C(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to two equivalent Na(1), one Fe(1), and one C(1) atom. In the third O site, O(3) is bonded in a distorted tetrahedral geometry to two equivalent Na(1), one Fe(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to two equivalent Na(1), one Fe(1), and one As(1) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to two equivalent Na(1), one Fe(1), and one As(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Na(1), one Fe(1), and one As(1) atom.
Na2FeCAsO7 crystallizes in the monoclinic P2_1/m space group. Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. The Na(1)-O(1) bond length is 2.28 Å. The Na(1)-O(2) bond length is 2.41 Å. The Na(1)-O(3) bond length is 2.38 Å. The Na(1)-O(4) bond length is 2.45 Å. The Na(1)-O(5) bond length is 2.94 Å. The Na(1)-O(6) bond length is 2.53 Å. Fe(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(6) atoms to form distorted FeO6 octahedra that share corners with four equivalent As(1)O4 tetrahedra. The Fe(1)-O(2) bond length is 2.13 Å. The Fe(1)-O(3) bond length is 2.09 Å. The Fe(1)-O(4) bond length is 2.02 Å. The Fe(1)-O(5) bond length is 2.00 Å. Both Fe(1)-O(6) bond lengths are 2.04 Å. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The C(1)-O(1) bond length is 1.26 Å. The C(1)-O(2) bond length is 1.31 Å. The C(1)-O(3) bond length is 1.33 Å. As(1) is bonded to one O(4), one O(5), and two equivalent O(6) atoms to form AsO4 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-54°. The As(1)-O(4) bond length is 1.72 Å. The As(1)-O(5) bond length is 1.74 Å. Both As(1)-O(6) bond lengths are 1.71 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Na(1) and one C(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to two equivalent Na(1), one Fe(1), and one C(1) atom. In the third O site, O(3) is bonded in a distorted tetrahedral geometry to two equivalent Na(1), one Fe(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to two equivalent Na(1), one Fe(1), and one As(1) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to two equivalent Na(1), one Fe(1), and one As(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Na(1), one Fe(1), and one As(1) atom.