Na2AsP(H4O5)2 crystallizes in the monoclinic P2_1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(2), one O(3), one O(5), one O(6), one O(7), and one O(9) atom to form distorted NaO6 octahedra that share corners with two equivalent Na(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and corners with three equivalent As(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-58°. In the second Na site, Na(2) is bonded to one O(1), one O(10), one O(4), one O(5), one O(6), and one O(8) atom to form distorted NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra,  a cornercorner with one As(1)O4 tetrahedra, and corners with three equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-58°. As(1) is bonded to one O(1), one O(3), one O(7), and one O(9) atom to form AsO4 tetrahedra that share  a cornercorner with one Na(2)O6 octahedra and corners with three equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-65°. P(1) is bonded to one O(10), one O(2), one O(4), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Na(1)O6 octahedra and corners with three equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-61°. There are eight inequivalent H sites. In the first H site, H(1) is bonded in a distorted single-bond geometry to one O(3) and one O(8) atom. In the second H site, H(2) is bonded in a distorted single-bond geometry to one O(4) and one O(7) atom. In the third H site, H(3) is bonded in a distorted linear geometry to one O(2) and one O(9) atom. In the fourth H site, H(4) is bonded in a linear geometry to one O(1) and one O(10) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(5) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one O(6) atom. In the seventh H site, H(7) is bonded in a single-bond geometry to one O(5) atom. In the eighth H site, H(8) is bonded in a single-bond geometry to one O(6) atom. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(2), one As(1), and one H(4) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one P(1), and one H(3) atom. In the third O site, O(3) is bonded in a 1-coordinate geometry to one Na(1), one As(1), and one H(1) atom. In the fourth O site, O(4) is bonded in a distorted water-like geometry to one Na(2), one P(1), and one H(2) atom. In the fifth O site, O(5) is bonded in a distorted water-like geometry to one Na(1), one Na(2), one H(5), and one H(7) atom. In the sixth O site, O(6) is bonded in a distorted water-like geometry to one Na(1), one Na(2), one H(6), and one H(8) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Na(1), one As(1), and one H(2) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(2), one P(1), and one H(1) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Na(1), one As(1), and one H(3) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Na(2), one P(1), and one H(4) atom.
Na2AsP(H4O5)2 crystallizes in the monoclinic P2_1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(2), one O(3), one O(5), one O(6), one O(7), and one O(9) atom to form distorted NaO6 octahedra that share corners with two equivalent Na(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and corners with three equivalent As(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-58°. The Na(1)-O(2) bond length is 2.40 Å. The Na(1)-O(3) bond length is 2.62 Å. The Na(1)-O(5) bond length is 2.50 Å. The Na(1)-O(6) bond length is 2.43 Å. The Na(1)-O(7) bond length is 2.47 Å. The Na(1)-O(9) bond length is 2.45 Å. In the second Na site, Na(2) is bonded to one O(1), one O(10), one O(4), one O(5), one O(6), and one O(8) atom to form distorted NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra,  a cornercorner with one As(1)O4 tetrahedra, and corners with three equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-58°. The Na(2)-O(1) bond length is 2.41 Å. The Na(2)-O(10) bond length is 2.49 Å. The Na(2)-O(4) bond length is 2.73 Å. The Na(2)-O(5) bond length is 2.45 Å. The Na(2)-O(6) bond length is 2.46 Å. The Na(2)-O(8) bond length is 2.54 Å. As(1) is bonded to one O(1), one O(3), one O(7), and one O(9) atom to form AsO4 tetrahedra that share  a cornercorner with one Na(2)O6 octahedra and corners with three equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-65°. The As(1)-O(1) bond length is 1.70 Å. The As(1)-O(3) bond length is 1.77 Å. The As(1)-O(7) bond length is 1.69 Å. The As(1)-O(9) bond length is 1.75 Å. P(1) is bonded to one O(10), one O(2), one O(4), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Na(1)O6 octahedra and corners with three equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-61°. The P(1)-O(10) bond length is 1.59 Å. The P(1)-O(2) bond length is 1.53 Å. The P(1)-O(4) bond length is 1.61 Å. The P(1)-O(8) bond length is 1.53 Å. There are eight inequivalent H sites. In the first H site, H(1) is bonded in a distorted single-bond geometry to one O(3) and one O(8) atom. The H(1)-O(3) bond length is 1.02 Å. The H(1)-O(8) bond length is 1.63 Å. In the second H site, H(2) is bonded in a distorted single-bond geometry to one O(4) and one O(7) atom. The H(2)-O(4) bond length is 1.02 Å. The H(2)-O(7) bond length is 1.63 Å. In the third H site, H(3) is bonded in a distorted linear geometry to one O(2) and one O(9) atom. The H(3)-O(2) bond length is 1.60 Å. The H(3)-O(9) bond length is 1.02 Å. In the fourth H site, H(4) is bonded in a linear geometry to one O(1) and one O(10) atom. The H(4)-O(1) bond length is 1.53 Å. The H(4)-O(10) bond length is 1.04 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(5) atom. The H(5)-O(5) bond length is 0.98 Å. In the sixth H site, H(6) is bonded in a single-bond geometry to one O(6) atom. The H(6)-O(6) bond length is 0.99 Å. In the seventh H site, H(7) is bonded in a single-bond geometry to one O(5) atom. The H(7)-O(5) bond length is 0.99 Å. In the eighth H site, H(8) is bonded in a single-bond geometry to one O(6) atom. The H(8)-O(6) bond length is 0.99 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(2), one As(1), and one H(4) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one P(1), and one H(3) atom. In the third O site, O(3) is bonded in a 1-coordinate geometry to one Na(1), one As(1), and one H(1) atom. In the fourth O site, O(4) is bonded in a distorted water-like geometry to one Na(2), one P(1), and one H(2) atom. In the fifth O site, O(5) is bonded in a distorted water-like geometry to one Na(1), one Na(2), one H(5), and one H(7) atom. In the sixth O site, O(6) is bonded in a distorted water-like geometry to one Na(1), one Na(2), one H(6), and one H(8) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Na(1), one As(1), and one H(2) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(2), one P(1), and one H(1) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Na(1), one As(1), and one H(3) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Na(2), one P(1), and one H(4) atom.