Na5Y(MoO4)4 crystallizes in the tetragonal I4_1/a space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to four equivalent O(4) atoms to form distorted NaO4 tetrahedra that share corners with eight equivalent Na(2)O6 pentagonal pyramids and corners with four equivalent Mo(1)O4 tetrahedra. In the second Na site, Na(2) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form distorted NaO6 pentagonal pyramids that share corners with two equivalent Na(1)O4 tetrahedra, corners with six equivalent Mo(1)O4 tetrahedra, and edges with two equivalent Na(2)O6 pentagonal pyramids. Y(1) is bonded in a 8-coordinate geometry to four equivalent O(2) and four equivalent O(3) atoms. Mo(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form MoO4 tetrahedra that share corners with six equivalent Na(2)O6 pentagonal pyramids and  a cornercorner with one Na(1)O4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Na(2) and one Mo(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Na(2), one Y(1), and one Mo(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Na(2), one Y(1), and one Mo(1) atom. In the fourth O site, O(4) is bonded to one Na(1), two equivalent Na(2), and one Mo(1) atom to form distorted corner-sharing ONa3Mo tetrahedra.
Na5Y(MoO4)4 crystallizes in the tetragonal I4_1/a space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to four equivalent O(4) atoms to form distorted NaO4 tetrahedra that share corners with eight equivalent Na(2)O6 pentagonal pyramids and corners with four equivalent Mo(1)O4 tetrahedra. All Na(1)-O(4) bond lengths are 2.45 Å. In the second Na site, Na(2) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form distorted NaO6 pentagonal pyramids that share corners with two equivalent Na(1)O4 tetrahedra, corners with six equivalent Mo(1)O4 tetrahedra, and edges with two equivalent Na(2)O6 pentagonal pyramids. The Na(2)-O(2) bond length is 2.39 Å. The Na(2)-O(3) bond length is 2.45 Å. There is one shorter (2.34 Å) and one longer (2.48 Å) Na(2)-O(1) bond length. There is one shorter (2.42 Å) and one longer (2.56 Å) Na(2)-O(4) bond length. Y(1) is bonded in a 8-coordinate geometry to four equivalent O(2) and four equivalent O(3) atoms. All Y(1)-O(2) bond lengths are 2.39 Å. All Y(1)-O(3) bond lengths are 2.40 Å. Mo(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form MoO4 tetrahedra that share corners with six equivalent Na(2)O6 pentagonal pyramids and  a cornercorner with one Na(1)O4 tetrahedra. The Mo(1)-O(1) bond length is 1.78 Å. The Mo(1)-O(2) bond length is 1.83 Å. The Mo(1)-O(3) bond length is 1.81 Å. The Mo(1)-O(4) bond length is 1.80 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Na(2) and one Mo(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Na(2), one Y(1), and one Mo(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Na(2), one Y(1), and one Mo(1) atom. In the fourth O site, O(4) is bonded to one Na(1), two equivalent Na(2), and one Mo(1) atom to form distorted corner-sharing ONa3Mo tetrahedra.