NaW2AsO9 crystallizes in the orthorhombic P2_12_12_1 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(6), and one O(8) atom. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(2), one O(3), one O(7), one O(9), and two equivalent O(8) atoms to form distorted WO6 octahedra that share corners with two equivalent W(1)O6 octahedra, corners with two equivalent W(2)O6 octahedra, and  a cornercorner with one As(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 24-40°. In the second W site, W(2) is bonded to one O(1), one O(4), one O(5), one O(6), one O(7), and one O(9) atom to form distorted WO6 octahedra that share corners with two equivalent W(1)O6 octahedra and corners with three equivalent As(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 24-40°. As(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form AsO4 tetrahedra that share  a cornercorner with one W(1)O6 octahedra and corners with three equivalent W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-54°. There are nine inequivalent O sites. In the first O site, O(5) is bonded in a bent 120 degrees geometry to one W(2) and one As(1) atom. In the second O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Na(1), one W(2), and one As(1) atom. In the third O site, O(7) is bonded in a bent 150 degrees geometry to one W(1) and one W(2) atom. In the fourth O site, O(8) is bonded in a distorted trigonal non-coplanar geometry to one Na(1) and two equivalent W(1) atoms. In the fifth O site, O(1) is bonded in a bent 150 degrees geometry to one Na(1) and one W(2) atom. In the sixth O site, O(9) is bonded in a bent 150 degrees geometry to one W(1) and one W(2) atom. In the seventh O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Na(1) and one W(1) atom. In the eighth O site, O(3) is bonded in a distorted trigonal planar geometry to one Na(1), one W(1), and one As(1) atom. In the ninth O site, O(4) is bonded in a distorted trigonal planar geometry to one Na(1), one W(2), and one As(1) atom.
NaW2AsO9 crystallizes in the orthorhombic P2_12_12_1 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(6), and one O(8) atom. The Na(1)-O(1) bond length is 2.47 Å. The Na(1)-O(2) bond length is 2.48 Å. The Na(1)-O(3) bond length is 2.46 Å. The Na(1)-O(4) bond length is 2.50 Å. The Na(1)-O(6) bond length is 2.97 Å. The Na(1)-O(8) bond length is 2.55 Å. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(2), one O(3), one O(7), one O(9), and two equivalent O(8) atoms to form distorted WO6 octahedra that share corners with two equivalent W(1)O6 octahedra, corners with two equivalent W(2)O6 octahedra, and  a cornercorner with one As(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 24-40°. The W(1)-O(2) bond length is 1.75 Å. The W(1)-O(3) bond length is 2.22 Å. The W(1)-O(7) bond length is 1.95 Å. The W(1)-O(9) bond length is 1.97 Å. There is one shorter (1.94 Å) and one longer (1.97 Å) W(1)-O(8) bond length. In the second W site, W(2) is bonded to one O(1), one O(4), one O(5), one O(6), one O(7), and one O(9) atom to form distorted WO6 octahedra that share corners with two equivalent W(1)O6 octahedra and corners with three equivalent As(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 24-40°. The W(2)-O(1) bond length is 1.76 Å. The W(2)-O(4) bond length is 2.17 Å. The W(2)-O(5) bond length is 2.03 Å. The W(2)-O(6) bond length is 2.02 Å. The W(2)-O(7) bond length is 1.92 Å. The W(2)-O(9) bond length is 1.91 Å. As(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form AsO4 tetrahedra that share  a cornercorner with one W(1)O6 octahedra and corners with three equivalent W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-54°. The As(1)-O(3) bond length is 1.70 Å. The As(1)-O(4) bond length is 1.71 Å. The As(1)-O(5) bond length is 1.73 Å. The As(1)-O(6) bond length is 1.73 Å. There are nine inequivalent O sites. In the first O site, O(5) is bonded in a bent 120 degrees geometry to one W(2) and one As(1) atom. In the second O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Na(1), one W(2), and one As(1) atom. In the third O site, O(7) is bonded in a bent 150 degrees geometry to one W(1) and one W(2) atom. In the fourth O site, O(8) is bonded in a distorted trigonal non-coplanar geometry to one Na(1) and two equivalent W(1) atoms. In the fifth O site, O(1) is bonded in a bent 150 degrees geometry to one Na(1) and one W(2) atom. In the sixth O site, O(9) is bonded in a bent 150 degrees geometry to one W(1) and one W(2) atom. In the seventh O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Na(1) and one W(1) atom. In the eighth O site, O(3) is bonded in a distorted trigonal planar geometry to one Na(1), one W(1), and one As(1) atom. In the ninth O site, O(4) is bonded in a distorted trigonal planar geometry to one Na(1), one W(2), and one As(1) atom.