Na2W3SeO14 crystallizes in the monoclinic Cc space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(10), one O(11), one O(12), one O(13), one O(4), one O(7), and one O(8) atom to form NaO7 pentagonal bipyramids that share  a cornercorner with one W(1)O6 octahedra,  a cornercorner with one W(2)O6 octahedra,  an edgeedge with one W(1)O6 octahedra,  an edgeedge with one W(2)O6 octahedra, and edges with two equivalent Na(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 45-48°. In the second Na site, Na(2) is bonded to one O(10), one O(11), one O(13), one O(14), one O(6), one O(7), and one O(9) atom to form NaO7 pentagonal bipyramids that share  a cornercorner with one W(2)O6 octahedra,  a cornercorner with one W(3)O6 octahedra,  an edgeedge with one W(1)O6 octahedra,  an edgeedge with one W(3)O6 octahedra, and edges with two equivalent Na(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 46-50°. There are three inequivalent W sites. In the first W site, W(1) is bonded to one O(1), one O(10), one O(12), one O(2), one O(4), and one O(6) atom to form distorted WO6 octahedra that share corners with two equivalent W(2)O6 octahedra, corners with two equivalent W(3)O6 octahedra,  a cornercorner with one Na(1)O7 pentagonal bipyramid,  an edgeedge with one Na(1)O7 pentagonal bipyramid, and  an edgeedge with one Na(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 29-46°. In the second W site, W(2) is bonded to one O(13), one O(2), one O(3), one O(4), one O(5), and one O(8) atom to form WO6 octahedra that share corners with two equivalent W(1)O6 octahedra, corners with two equivalent W(3)O6 octahedra,  a cornercorner with one Na(1)O7 pentagonal bipyramid,  a cornercorner with one Na(2)O7 pentagonal bipyramid, and  an edgeedge with one Na(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 29-46°. In the third W site, W(3) is bonded to one O(1), one O(14), one O(3), one O(5), one O(6), and one O(9) atom to form distorted WO6 octahedra that share corners with two equivalent W(1)O6 octahedra, corners with two equivalent W(2)O6 octahedra,  a cornercorner with one Na(2)O7 pentagonal bipyramid, and  an edgeedge with one Na(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 29-44°. Se(1) is bonded in a trigonal non-coplanar geometry to one O(10), one O(8), and one O(9) atom. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one W(1) and one W(3) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one W(1) and one W(2) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one W(2) and one W(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Na(1), one W(1), and one W(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one W(2) and one W(3) atom. In the sixth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one Na(2), one W(1), and one W(3) atom. In the seventh O site, O(7) is bonded in a water-like geometry to one Na(1) and one Na(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal non-coplanar geometry to one Na(1), one W(2), and one Se(1) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Na(2), one W(3), and one Se(1) atom. In the tenth O site, O(10) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one W(1), and one Se(1) atom. In the eleventh O site, O(11) is bonded in an L-shaped geometry to one Na(1) and one Na(2) atom. In the twelfth O site, O(12) is bonded in a distorted bent 150 degrees geometry to one Na(1) and one W(1) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Na(1), one Na(2), and one W(2) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 120 degrees geometry to one Na(2) and one W(3) atom.
Na2W3SeO14 crystallizes in the monoclinic Cc space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(10), one O(11), one O(12), one O(13), one O(4), one O(7), and one O(8) atom to form NaO7 pentagonal bipyramids that share  a cornercorner with one W(1)O6 octahedra,  a cornercorner with one W(2)O6 octahedra,  an edgeedge with one W(1)O6 octahedra,  an edgeedge with one W(2)O6 octahedra, and edges with two equivalent Na(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 45-48°. The Na(1)-O(10) bond length is 2.66 Å. The Na(1)-O(11) bond length is 2.50 Å. The Na(1)-O(12) bond length is 2.38 Å. The Na(1)-O(13) bond length is 2.44 Å. The Na(1)-O(4) bond length is 2.51 Å. The Na(1)-O(7) bond length is 2.48 Å. The Na(1)-O(8) bond length is 2.51 Å. In the second Na site, Na(2) is bonded to one O(10), one O(11), one O(13), one O(14), one O(6), one O(7), and one O(9) atom to form NaO7 pentagonal bipyramids that share  a cornercorner with one W(2)O6 octahedra,  a cornercorner with one W(3)O6 octahedra,  an edgeedge with one W(1)O6 octahedra,  an edgeedge with one W(3)O6 octahedra, and edges with two equivalent Na(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 46-50°. The Na(2)-O(10) bond length is 2.63 Å. The Na(2)-O(11) bond length is 2.48 Å. The Na(2)-O(13) bond length is 2.46 Å. The Na(2)-O(14) bond length is 2.39 Å. The Na(2)-O(6) bond length is 2.57 Å. The Na(2)-O(7) bond length is 2.48 Å. The Na(2)-O(9) bond length is 2.56 Å. There are three inequivalent W sites. In the first W site, W(1) is bonded to one O(1), one O(10), one O(12), one O(2), one O(4), and one O(6) atom to form distorted WO6 octahedra that share corners with two equivalent W(2)O6 octahedra, corners with two equivalent W(3)O6 octahedra,  a cornercorner with one Na(1)O7 pentagonal bipyramid,  an edgeedge with one Na(1)O7 pentagonal bipyramid, and  an edgeedge with one Na(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 29-46°. The W(1)-O(1) bond length is 1.93 Å. The W(1)-O(10) bond length is 2.23 Å. The W(1)-O(12) bond length is 1.76 Å. The W(1)-O(2) bond length is 1.94 Å. The W(1)-O(4) bond length is 1.96 Å. The W(1)-O(6) bond length is 1.98 Å. In the second W site, W(2) is bonded to one O(13), one O(2), one O(3), one O(4), one O(5), and one O(8) atom to form WO6 octahedra that share corners with two equivalent W(1)O6 octahedra, corners with two equivalent W(3)O6 octahedra,  a cornercorner with one Na(1)O7 pentagonal bipyramid,  a cornercorner with one Na(2)O7 pentagonal bipyramid, and  an edgeedge with one Na(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 29-46°. The W(2)-O(13) bond length is 1.79 Å. The W(2)-O(2) bond length is 1.92 Å. The W(2)-O(3) bond length is 1.96 Å. The W(2)-O(4) bond length is 1.97 Å. The W(2)-O(5) bond length is 1.94 Å. The W(2)-O(8) bond length is 2.17 Å. In the third W site, W(3) is bonded to one O(1), one O(14), one O(3), one O(5), one O(6), and one O(9) atom to form distorted WO6 octahedra that share corners with two equivalent W(1)O6 octahedra, corners with two equivalent W(2)O6 octahedra,  a cornercorner with one Na(2)O7 pentagonal bipyramid, and  an edgeedge with one Na(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 29-44°. The W(3)-O(1) bond length is 1.95 Å. The W(3)-O(14) bond length is 1.77 Å. The W(3)-O(3) bond length is 1.94 Å. The W(3)-O(5) bond length is 1.98 Å. The W(3)-O(6) bond length is 1.96 Å. The W(3)-O(9) bond length is 2.20 Å. Se(1) is bonded in a trigonal non-coplanar geometry to one O(10), one O(8), and one O(9) atom. The Se(1)-O(10) bond length is 1.76 Å. The Se(1)-O(8) bond length is 1.74 Å. The Se(1)-O(9) bond length is 1.74 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one W(1) and one W(3) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one W(1) and one W(2) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one W(2) and one W(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Na(1), one W(1), and one W(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one W(2) and one W(3) atom. In the sixth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one Na(2), one W(1), and one W(3) atom. In the seventh O site, O(7) is bonded in a water-like geometry to one Na(1) and one Na(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal non-coplanar geometry to one Na(1), one W(2), and one Se(1) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Na(2), one W(3), and one Se(1) atom. In the tenth O site, O(10) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one W(1), and one Se(1) atom. In the eleventh O site, O(11) is bonded in an L-shaped geometry to one Na(1) and one Na(2) atom. In the twelfth O site, O(12) is bonded in a distorted bent 150 degrees geometry to one Na(1) and one W(1) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Na(1), one Na(2), and one W(2) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 120 degrees geometry to one Na(2) and one W(3) atom.