NaPO4 crystallizes in the triclinic P-1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(2), one O(5), and two equivalent O(4) atoms to form distorted NaO5 trigonal bipyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one Na(1)O5 trigonal bipyramid. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(2), one O(5), two equivalent O(7), and two equivalent O(8) atoms. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with two equivalent P(2)O4 tetrahedra and corners with three equivalent Na(1)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(1), one O(2), one O(3), and one O(6) atom to form PO4 tetrahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with two equivalent Na(1)O5 trigonal bipyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Na(1) and one P(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one P(2) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one P(1) and one P(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Na(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one P(1) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to two equivalent Na(2) and one O(7) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to two equivalent Na(2) atoms.
NaPO4 crystallizes in the triclinic P-1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(2), one O(5), and two equivalent O(4) atoms to form distorted NaO5 trigonal bipyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one Na(1)O5 trigonal bipyramid. The Na(1)-O(1) bond length is 2.36 Å. The Na(1)-O(2) bond length is 2.66 Å. The Na(1)-O(5) bond length is 2.30 Å. There is one shorter (2.28 Å) and one longer (2.35 Å) Na(1)-O(4) bond length. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(2), one O(5), two equivalent O(7), and two equivalent O(8) atoms. The Na(2)-O(2) bond length is 2.27 Å. The Na(2)-O(5) bond length is 2.24 Å. There is one shorter (2.51 Å) and one longer (2.55 Å) Na(2)-O(7) bond length. There is one shorter (2.37 Å) and one longer (2.97 Å) Na(2)-O(8) bond length. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with two equivalent P(2)O4 tetrahedra and corners with three equivalent Na(1)O5 trigonal bipyramids. The P(1)-O(3) bond length is 1.64 Å. The P(1)-O(4) bond length is 1.50 Å. The P(1)-O(5) bond length is 1.49 Å. The P(1)-O(6) bond length is 1.63 Å. In the second P site, P(2) is bonded to one O(1), one O(2), one O(3), and one O(6) atom to form PO4 tetrahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with two equivalent Na(1)O5 trigonal bipyramids. The P(2)-O(1) bond length is 1.51 Å. The P(2)-O(2) bond length is 1.51 Å. The P(2)-O(3) bond length is 1.62 Å. The P(2)-O(6) bond length is 1.63 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Na(1) and one P(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one P(2) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one P(1) and one P(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Na(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one P(1) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to two equivalent Na(2) and one O(7) atom. The O(7)-O(7) bond length is 1.24 Å. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to two equivalent Na(2) atoms.