Na3CuCPO7 crystallizes in the monoclinic P2_1 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form NaO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra and edges with two equivalent Na(1)O6 octahedra. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one C(1), one O(1), one O(2), one O(3), one O(4), and one O(6) atom. In the third Na site, Na(3) is bonded to two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms to form distorted NaO6 octahedra that share corners with four equivalent P(1)O4 tetrahedra and faces with two equivalent Na(3)O6 octahedra. Cu(1) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(4), and one O(7) atom. C(1) is bonded in a trigonal planar geometry to one Na(2), one O(1), one O(2), and one O(5) atom. P(1) is bonded to one O(3), one O(4), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Na(1)O6 octahedra and corners with four equivalent Na(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-66°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Na(2), two equivalent Na(1), and one C(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(2), two equivalent Na(1), one Cu(1), and one C(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Cu(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), one Cu(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to two equivalent Na(3) and one C(1) atom. In the sixth O site, O(6) is bonded to one Na(2), two equivalent Na(3), and one P(1) atom to form distorted corner-sharing ONa3P tetrahedra. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to two equivalent Na(3), one Cu(1), and one P(1) atom.
Na3CuCPO7 crystallizes in the monoclinic P2_1 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form NaO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra and edges with two equivalent Na(1)O6 octahedra. The Na(1)-O(3) bond length is 2.43 Å. The Na(1)-O(4) bond length is 2.31 Å. There is one shorter (2.41 Å) and one longer (2.43 Å) Na(1)-O(1) bond length. There is one shorter (2.33 Å) and one longer (2.37 Å) Na(1)-O(2) bond length. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one C(1), one O(1), one O(2), one O(3), one O(4), and one O(6) atom. The Na(2)-C(1) bond length is 2.88 Å. The Na(2)-O(1) bond length is 2.35 Å. The Na(2)-O(2) bond length is 2.61 Å. The Na(2)-O(3) bond length is 2.42 Å. The Na(2)-O(4) bond length is 2.93 Å. The Na(2)-O(6) bond length is 2.25 Å. In the third Na site, Na(3) is bonded to two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms to form distorted NaO6 octahedra that share corners with four equivalent P(1)O4 tetrahedra and faces with two equivalent Na(3)O6 octahedra. There is one shorter (2.47 Å) and one longer (2.68 Å) Na(3)-O(5) bond length. Both Na(3)-O(6) bond lengths are 2.24 Å. There is one shorter (2.60 Å) and one longer (2.68 Å) Na(3)-O(7) bond length. Cu(1) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(4), and one O(7) atom. The Cu(1)-O(2) bond length is 2.09 Å. The Cu(1)-O(3) bond length is 2.05 Å. The Cu(1)-O(4) bond length is 2.02 Å. The Cu(1)-O(7) bond length is 1.98 Å. C(1) is bonded in a trigonal planar geometry to one Na(2), one O(1), one O(2), and one O(5) atom. The C(1)-O(1) bond length is 1.29 Å. The C(1)-O(2) bond length is 1.34 Å. The C(1)-O(5) bond length is 1.27 Å. P(1) is bonded to one O(3), one O(4), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Na(1)O6 octahedra and corners with four equivalent Na(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-66°. The P(1)-O(3) bond length is 1.58 Å. The P(1)-O(4) bond length is 1.56 Å. The P(1)-O(6) bond length is 1.53 Å. The P(1)-O(7) bond length is 1.56 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Na(2), two equivalent Na(1), and one C(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(2), two equivalent Na(1), one Cu(1), and one C(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Cu(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), one Cu(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to two equivalent Na(3) and one C(1) atom. In the sixth O site, O(6) is bonded to one Na(2), two equivalent Na(3), and one P(1) atom to form distorted corner-sharing ONa3P tetrahedra. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to two equivalent Na(3), one Cu(1), and one P(1) atom.