Y2Mo2O7 crystallizes in the monoclinic C2/c space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a distorted body-centered cubic geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. In the second Y site, Y(2) is bonded in a distorted body-centered cubic geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form corner-sharing MoO6 octahedra. The corner-sharing octahedral tilt angles range from 52-54°. In the second Mo site, Mo(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form corner-sharing MoO6 octahedra. The corner-sharing octahedral tilt angles range from 52-55°. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Y(1) and two equivalent Y(2) atoms to form OY4 tetrahedra that share corners with two equivalent O(4)Y2Mo2 tetrahedra, corners with two equivalent O(5)Y2Mo2 tetrahedra, corners with four equivalent O(2)Y2Mo2 tetrahedra, corners with four equivalent O(3)Y2Mo2 tetrahedra, corners with four equivalent O(1)Y4 tetrahedra,  an edgeedge with one O(4)Y2Mo2 tetrahedra,  an edgeedge with one O(5)Y2Mo2 tetrahedra, edges with two equivalent O(2)Y2Mo2 tetrahedra, and edges with two equivalent O(3)Y2Mo2 tetrahedra. In the second O site, O(2) is bonded to one Y(1), one Y(2), one Mo(1), and one Mo(2) atom to form distorted OY2Mo2 tetrahedra that share corners with two equivalent O(4)Y2Mo2 tetrahedra, corners with two equivalent O(5)Y2Mo2 tetrahedra, corners with two equivalent O(1)Y4 tetrahedra, corners with four equivalent O(2)Y2Mo2 tetrahedra, corners with four equivalent O(3)Y2Mo2 tetrahedra,  an edgeedge with one O(4)Y2Mo2 tetrahedra,  an edgeedge with one O(5)Y2Mo2 tetrahedra,  an edgeedge with one O(1)Y4 tetrahedra, and edges with two equivalent O(3)Y2Mo2 tetrahedra. In the third O site, O(3) is bonded to one Y(1), one Y(2), one Mo(1), and one Mo(2) atom to form distorted OY2Mo2 tetrahedra that share corners with two equivalent O(4)Y2Mo2 tetrahedra, corners with two equivalent O(5)Y2Mo2 tetrahedra, corners with two equivalent O(1)Y4 tetrahedra, corners with four equivalent O(2)Y2Mo2 tetrahedra, corners with four equivalent O(3)Y2Mo2 tetrahedra,  an edgeedge with one O(4)Y2Mo2 tetrahedra,  an edgeedge with one O(5)Y2Mo2 tetrahedra,  an edgeedge with one O(1)Y4 tetrahedra, and edges with two equivalent O(2)Y2Mo2 tetrahedra. In the fourth O site, O(4) is bonded to two equivalent Y(2) and two equivalent Mo(1) atoms to form distorted OY2Mo2 tetrahedra that share corners with two equivalent O(1)Y4 tetrahedra, corners with four equivalent O(2)Y2Mo2 tetrahedra, corners with four equivalent O(3)Y2Mo2 tetrahedra, corners with four equivalent O(4)Y2Mo2 tetrahedra,  an edgeedge with one O(1)Y4 tetrahedra, edges with two equivalent O(2)Y2Mo2 tetrahedra, and edges with two equivalent O(3)Y2Mo2 tetrahedra. In the fifth O site, O(5) is bonded to two equivalent Y(1) and two equivalent Mo(2) atoms to form OY2Mo2 tetrahedra that share corners with two equivalent O(1)Y4 tetrahedra, corners with four equivalent O(2)Y2Mo2 tetrahedra, corners with four equivalent O(3)Y2Mo2 tetrahedra, corners with four equivalent O(5)Y2Mo2 tetrahedra,  an edgeedge with one O(1)Y4 tetrahedra, edges with two equivalent O(2)Y2Mo2 tetrahedra, and edges with two equivalent O(3)Y2Mo2 tetrahedra.
Y2Mo2O7 crystallizes in the monoclinic C2/c space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a distorted body-centered cubic geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. Both Y(1)-O(1) bond lengths are 2.23 Å. Both Y(1)-O(2) bond lengths are 2.41 Å. Both Y(1)-O(3) bond lengths are 2.54 Å. Both Y(1)-O(5) bond lengths are 2.44 Å. In the second Y site, Y(2) is bonded in a distorted body-centered cubic geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. Both Y(2)-O(1) bond lengths are 2.22 Å. Both Y(2)-O(2) bond lengths are 2.50 Å. Both Y(2)-O(3) bond lengths are 2.42 Å. Both Y(2)-O(4) bond lengths are 2.47 Å. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form corner-sharing MoO6 octahedra. The corner-sharing octahedral tilt angles range from 52-54°. Both Mo(1)-O(2) bond lengths are 1.99 Å. Both Mo(1)-O(3) bond lengths are 2.04 Å. Both Mo(1)-O(4) bond lengths are 2.02 Å. In the second Mo site, Mo(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form corner-sharing MoO6 octahedra. The corner-sharing octahedral tilt angles range from 52-55°. Both Mo(2)-O(2) bond lengths are 2.07 Å. Both Mo(2)-O(3) bond lengths are 2.00 Å. Both Mo(2)-O(5) bond lengths are 2.04 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Y(1) and two equivalent Y(2) atoms to form OY4 tetrahedra that share corners with two equivalent O(4)Y2Mo2 tetrahedra, corners with two equivalent O(5)Y2Mo2 tetrahedra, corners with four equivalent O(2)Y2Mo2 tetrahedra, corners with four equivalent O(3)Y2Mo2 tetrahedra, corners with four equivalent O(1)Y4 tetrahedra,  an edgeedge with one O(4)Y2Mo2 tetrahedra,  an edgeedge with one O(5)Y2Mo2 tetrahedra, edges with two equivalent O(2)Y2Mo2 tetrahedra, and edges with two equivalent O(3)Y2Mo2 tetrahedra. In the second O site, O(2) is bonded to one Y(1), one Y(2), one Mo(1), and one Mo(2) atom to form distorted OY2Mo2 tetrahedra that share corners with two equivalent O(4)Y2Mo2 tetrahedra, corners with two equivalent O(5)Y2Mo2 tetrahedra, corners with two equivalent O(1)Y4 tetrahedra, corners with four equivalent O(2)Y2Mo2 tetrahedra, corners with four equivalent O(3)Y2Mo2 tetrahedra,  an edgeedge with one O(4)Y2Mo2 tetrahedra,  an edgeedge with one O(5)Y2Mo2 tetrahedra,  an edgeedge with one O(1)Y4 tetrahedra, and edges with two equivalent O(3)Y2Mo2 tetrahedra. In the third O site, O(3) is bonded to one Y(1), one Y(2), one Mo(1), and one Mo(2) atom to form distorted OY2Mo2 tetrahedra that share corners with two equivalent O(4)Y2Mo2 tetrahedra, corners with two equivalent O(5)Y2Mo2 tetrahedra, corners with two equivalent O(1)Y4 tetrahedra, corners with four equivalent O(2)Y2Mo2 tetrahedra, corners with four equivalent O(3)Y2Mo2 tetrahedra,  an edgeedge with one O(4)Y2Mo2 tetrahedra,  an edgeedge with one O(5)Y2Mo2 tetrahedra,  an edgeedge with one O(1)Y4 tetrahedra, and edges with two equivalent O(2)Y2Mo2 tetrahedra. In the fourth O site, O(4) is bonded to two equivalent Y(2) and two equivalent Mo(1) atoms to form distorted OY2Mo2 tetrahedra that share corners with two equivalent O(1)Y4 tetrahedra, corners with four equivalent O(2)Y2Mo2 tetrahedra, corners with four equivalent O(3)Y2Mo2 tetrahedra, corners with four equivalent O(4)Y2Mo2 tetrahedra,  an edgeedge with one O(1)Y4 tetrahedra, edges with two equivalent O(2)Y2Mo2 tetrahedra, and edges with two equivalent O(3)Y2Mo2 tetrahedra. In the fifth O site, O(5) is bonded to two equivalent Y(1) and two equivalent Mo(2) atoms to form OY2Mo2 tetrahedra that share corners with two equivalent O(1)Y4 tetrahedra, corners with four equivalent O(2)Y2Mo2 tetrahedra, corners with four equivalent O(3)Y2Mo2 tetrahedra, corners with four equivalent O(5)Y2Mo2 tetrahedra,  an edgeedge with one O(1)Y4 tetrahedra, edges with two equivalent O(2)Y2Mo2 tetrahedra, and edges with two equivalent O(3)Y2Mo2 tetrahedra.