Na3TlCPO7 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms. In the second Na site, Na(2) 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 distorted NaO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra,  an edgeedge with one Na(2)O6 octahedra, and  a faceface with one Na(2)O6 octahedra. Tl(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. P(1) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with six equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-65°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and one C(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(2), one Tl(1), and one C(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Na(1), two equivalent Na(2), one Tl(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(2), one Tl(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted tetrahedral geometry to two equivalent Na(2), one Tl(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to two equivalent Na(2), one Tl(1), and one P(1) atom.
Na3TlCPO7 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms. The Na(1)-O(2) bond length is 2.39 Å. The Na(1)-O(3) bond length is 2.50 Å. There is one shorter (2.54 Å) and one longer (2.80 Å) Na(1)-O(1) bond length. Both Na(1)-O(4) bond lengths are 2.56 Å. In the second Na site, Na(2) 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 distorted NaO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra,  an edgeedge with one Na(2)O6 octahedra, and  a faceface with one Na(2)O6 octahedra. The Na(2)-O(1) bond length is 2.41 Å. The Na(2)-O(2) bond length is 2.73 Å. The Na(2)-O(3) bond length is 2.68 Å. The Na(2)-O(4) bond length is 2.44 Å. The Na(2)-O(5) bond length is 2.38 Å. The Na(2)-O(6) bond length is 2.52 Å. Tl(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms. The Tl(1)-O(2) bond length is 2.67 Å. The Tl(1)-O(3) bond length is 2.61 Å. The Tl(1)-O(5) bond length is 2.45 Å. The Tl(1)-O(6) bond length is 2.55 Å. Both Tl(1)-O(4) bond lengths are 2.44 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 1.30 Å. The C(1)-O(2) bond length is 1.31 Å. The C(1)-O(3) bond length is 1.31 Å. P(1) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with six equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-65°. The P(1)-O(5) bond length is 1.56 Å. The P(1)-O(6) bond length is 1.56 Å. Both P(1)-O(4) bond lengths are 1.57 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and one C(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(2), one Tl(1), and one C(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Na(1), two equivalent Na(2), one Tl(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(2), one Tl(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted tetrahedral geometry to two equivalent Na(2), one Tl(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to two equivalent Na(2), one Tl(1), and one P(1) atom.