NaH2PO4 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(3), one O(4), one O(5), and two equivalent O(2) atoms to form NaO5 square pyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra,  an edgeedge with one Na(2)O6 octahedra, and  an edgeedge with one Na(1)O5 square pyramid. In the second Na site, Na(2) is bonded to one O(3), one O(5), two equivalent O(7), and two equivalent O(8) atoms to form NaO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, edges with two equivalent Na(2)O6 octahedra, and  an edgeedge with one Na(1)O5 square pyramid. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Na(2)O6 octahedra, corners with three equivalent Na(1)O5 square pyramids, and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. In the second P site, P(2) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Na(2)O6 octahedra, corners with two equivalent Na(1)O5 square pyramids, and corners with two equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 53°. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(7) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(7) atom. In the third H site, H(3) is bonded in a single-bond geometry to one O(4) and one O(8) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(8) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Na(1) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one P(2), and one H(3) 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(2) 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 water-like geometry to two equivalent Na(2), one H(1), and one H(2) atom. In the eighth O site, O(8) is bonded in a distorted water-like geometry to two equivalent Na(2), one H(3), and one H(4) atom.
NaH2PO4 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(3), one O(4), one O(5), and two equivalent O(2) atoms to form NaO5 square pyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra,  an edgeedge with one Na(2)O6 octahedra, and  an edgeedge with one Na(1)O5 square pyramid. The Na(1)-O(3) bond length is 2.23 Å. The Na(1)-O(4) bond length is 2.32 Å. The Na(1)-O(5) bond length is 2.42 Å. There is one shorter (2.30 Å) and one longer (2.38 Å) Na(1)-O(2) bond length. In the second Na site, Na(2) is bonded to one O(3), one O(5), two equivalent O(7), and two equivalent O(8) atoms to form NaO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, edges with two equivalent Na(2)O6 octahedra, and  an edgeedge with one Na(1)O5 square pyramid. The Na(2)-O(3) bond length is 2.41 Å. The Na(2)-O(5) bond length is 2.42 Å. There is one shorter (2.43 Å) and one longer (2.47 Å) Na(2)-O(7) bond length. Both Na(2)-O(8) bond lengths are 2.37 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(3), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Na(2)O6 octahedra, corners with three equivalent Na(1)O5 square pyramids, and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. The P(1)-O(1) bond length is 1.60 Å. The P(1)-O(2) bond length is 1.49 Å. The P(1)-O(3) bond length is 1.47 Å. The P(1)-O(6) bond length is 1.61 Å. In the second P site, P(2) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Na(2)O6 octahedra, corners with two equivalent Na(1)O5 square pyramids, and corners with two equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 53°. The P(2)-O(1) bond length is 1.59 Å. The P(2)-O(4) bond length is 1.49 Å. The P(2)-O(5) bond length is 1.48 Å. The P(2)-O(6) bond length is 1.60 Å. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(7) atom. The H(1)-O(7) bond length is 0.97 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(7) atom. The H(2)-O(7) bond length is 0.98 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(4) and one O(8) atom. The H(3)-O(4) bond length is 1.70 Å. The H(3)-O(8) bond length is 0.98 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(8) atom. The H(4)-O(8) bond length is 0.98 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Na(1) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one P(2), and one H(3) 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(2) 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 water-like geometry to two equivalent Na(2), one H(1), and one H(2) atom. In the eighth O site, O(8) is bonded in a distorted water-like geometry to two equivalent Na(2), one H(3), and one H(4) atom.