NaTiP2O7 crystallizes in the monoclinic P2_1/c 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. Ti(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form TiO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Ti(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-54°. In the second P site, P(2) is bonded to one O(1), one O(3), one O(4), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Ti(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 18-51°. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a 3-coordinate geometry to one Na(1), one Ti(1), and one P(1) atom. In the second O site, O(6) is bonded in a 3-coordinate geometry to one Na(1), one Ti(1), and one P(1) atom. In the third O site, O(7) is bonded in a distorted linear geometry to one Ti(1) and one P(2) atom. In the fourth O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one P(1), and one P(2) atom. In the fifth O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Ti(1), and one P(1) atom. In the sixth O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), one Ti(1), and one P(2) atom. In the seventh O site, O(4) is bonded in a distorted trigonal planar geometry to one Na(1), one Ti(1), and one P(2) atom.
NaTiP2O7 crystallizes in the monoclinic P2_1/c 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 2.56 Å. The Na(1)-O(2) bond length is 2.50 Å. The Na(1)-O(3) bond length is 2.64 Å. The Na(1)-O(4) bond length is 2.46 Å. The Na(1)-O(5) bond length is 2.44 Å. The Na(1)-O(6) bond length is 2.74 Å. Ti(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form TiO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. The Ti(1)-O(2) bond length is 2.12 Å. The Ti(1)-O(3) bond length is 2.05 Å. The Ti(1)-O(4) bond length is 2.07 Å. The Ti(1)-O(5) bond length is 2.01 Å. The Ti(1)-O(6) bond length is 2.11 Å. The Ti(1)-O(7) bond length is 2.02 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Ti(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-54°. The P(1)-O(1) bond length is 1.63 Å. The P(1)-O(2) bond length is 1.54 Å. The P(1)-O(5) bond length is 1.53 Å. The P(1)-O(6) bond length is 1.53 Å. In the second P site, P(2) is bonded to one O(1), one O(3), one O(4), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Ti(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 18-51°. The P(2)-O(1) bond length is 1.63 Å. The P(2)-O(3) bond length is 1.53 Å. The P(2)-O(4) bond length is 1.54 Å. The P(2)-O(7) bond length is 1.51 Å. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a 3-coordinate geometry to one Na(1), one Ti(1), and one P(1) atom. In the second O site, O(6) is bonded in a 3-coordinate geometry to one Na(1), one Ti(1), and one P(1) atom. In the third O site, O(7) is bonded in a distorted linear geometry to one Ti(1) and one P(2) atom. In the fourth O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one P(1), and one P(2) atom. In the fifth O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Ti(1), and one P(1) atom. In the sixth O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), one Ti(1), and one P(2) atom. In the seventh O site, O(4) is bonded in a distorted trigonal planar geometry to one Na(1), one Ti(1), and one P(2) atom.