Y3ReO8 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Y sites. In the first Y site, Y(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(7) atoms. In the second Y site, Y(2) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(7), one O(8), two equivalent O(5), and two equivalent O(6) atoms. In the third Y site, Y(3) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(8) atoms. Re(1) is bonded in an octahedral geometry to one O(1), one O(2), one O(3), one O(4), one O(7), and one O(8) atom. There are eight inequivalent O sites. In the first O site, O(5) is bonded to one Y(1), one Y(3), and two equivalent Y(2) atoms to form distorted OY4 trigonal pyramids that share corners with two equivalent O(7)Y3Re tetrahedra, corners with two equivalent O(5)Y4 trigonal pyramids, corners with four equivalent O(2)Y3Re trigonal pyramids,  an edgeedge with one O(7)Y3Re tetrahedra, and edges with three equivalent O(6)Y4 tetrahedra. In the second O site, O(6) is bonded to one Y(1), one Y(3), and two equivalent Y(2) atoms to form distorted OY4 tetrahedra that share corners with two equivalent O(6)Y4 tetrahedra, corners with four equivalent O(7)Y3Re tetrahedra, corners with four equivalent O(2)Y3Re trigonal pyramids, and edges with three equivalent O(5)Y4 trigonal pyramids. In the third O site, O(7) is bonded to one Y(2), two equivalent Y(1), and one Re(1) atom to form distorted OY3Re tetrahedra that share corners with four equivalent O(6)Y4 tetrahedra, corners with two equivalent O(2)Y3Re trigonal pyramids, corners with two equivalent O(5)Y4 trigonal pyramids,  an edgeedge with one O(7)Y3Re tetrahedra,  an edgeedge with one O(2)Y3Re trigonal pyramid, and  an edgeedge with one O(5)Y4 trigonal pyramid. In the fourth O site, O(8) is bonded in a 4-coordinate geometry to one Y(2), two equivalent Y(3), and one Re(1) atom. In the fifth O site, O(1) is bonded in a distorted single-bond geometry to one Y(1), one Y(3), and one Re(1) atom. In the sixth O site, O(2) is bonded to one Y(1), one Y(2), one Y(3), and one Re(1) atom to form distorted OY3Re trigonal pyramids that share corners with two equivalent O(7)Y3Re tetrahedra, corners with four equivalent O(6)Y4 tetrahedra, corners with four equivalent O(5)Y4 trigonal pyramids, and  an edgeedge with one O(7)Y3Re tetrahedra. In the seventh O site, O(3) is bonded in a 4-coordinate geometry to one Y(1), one Y(2), one Y(3), and one Re(1) atom. In the eighth O site, O(4) is bonded in a distorted trigonal planar geometry to one Y(1), one Y(3), and one Re(1) atom.
Y3ReO8 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Y sites. In the first Y site, Y(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(7) atoms. The Y(1)-O(1) bond length is 2.54 Å. The Y(1)-O(2) bond length is 2.54 Å. The Y(1)-O(3) bond length is 2.37 Å. The Y(1)-O(4) bond length is 2.27 Å. The Y(1)-O(5) bond length is 2.25 Å. The Y(1)-O(6) bond length is 2.18 Å. There is one shorter (2.39 Å) and one longer (2.52 Å) Y(1)-O(7) bond length. In the second Y site, Y(2) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(7), one O(8), two equivalent O(5), and two equivalent O(6) atoms. The Y(2)-O(2) bond length is 2.48 Å. The Y(2)-O(3) bond length is 2.56 Å. The Y(2)-O(7) bond length is 2.49 Å. The Y(2)-O(8) bond length is 2.53 Å. There is one shorter (2.33 Å) and one longer (2.37 Å) Y(2)-O(5) bond length. There is one shorter (2.30 Å) and one longer (2.36 Å) Y(2)-O(6) bond length. In the third Y site, Y(3) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(8) atoms. The Y(3)-O(1) bond length is 2.52 Å. The Y(3)-O(2) bond length is 2.56 Å. The Y(3)-O(3) bond length is 2.33 Å. The Y(3)-O(4) bond length is 2.24 Å. The Y(3)-O(5) bond length is 2.23 Å. The Y(3)-O(6) bond length is 2.24 Å. There is one shorter (2.38 Å) and one longer (2.56 Å) Y(3)-O(8) bond length. Re(1) is bonded in an octahedral geometry to one O(1), one O(2), one O(3), one O(4), one O(7), and one O(8) atom. The Re(1)-O(1) bond length is 1.81 Å. The Re(1)-O(2) bond length is 1.89 Å. The Re(1)-O(3) bond length is 1.96 Å. The Re(1)-O(4) bond length is 1.85 Å. The Re(1)-O(7) bond length is 1.89 Å. The Re(1)-O(8) bond length is 1.91 Å. There are eight inequivalent O sites. In the first O site, O(5) is bonded to one Y(1), one Y(3), and two equivalent Y(2) atoms to form distorted OY4 trigonal pyramids that share corners with two equivalent O(7)Y3Re tetrahedra, corners with two equivalent O(5)Y4 trigonal pyramids, corners with four equivalent O(2)Y3Re trigonal pyramids,  an edgeedge with one O(7)Y3Re tetrahedra, and edges with three equivalent O(6)Y4 tetrahedra. In the second O site, O(6) is bonded to one Y(1), one Y(3), and two equivalent Y(2) atoms to form distorted OY4 tetrahedra that share corners with two equivalent O(6)Y4 tetrahedra, corners with four equivalent O(7)Y3Re tetrahedra, corners with four equivalent O(2)Y3Re trigonal pyramids, and edges with three equivalent O(5)Y4 trigonal pyramids. In the third O site, O(7) is bonded to one Y(2), two equivalent Y(1), and one Re(1) atom to form distorted OY3Re tetrahedra that share corners with four equivalent O(6)Y4 tetrahedra, corners with two equivalent O(2)Y3Re trigonal pyramids, corners with two equivalent O(5)Y4 trigonal pyramids,  an edgeedge with one O(7)Y3Re tetrahedra,  an edgeedge with one O(2)Y3Re trigonal pyramid, and  an edgeedge with one O(5)Y4 trigonal pyramid. In the fourth O site, O(8) is bonded in a 4-coordinate geometry to one Y(2), two equivalent Y(3), and one Re(1) atom. In the fifth O site, O(1) is bonded in a distorted single-bond geometry to one Y(1), one Y(3), and one Re(1) atom. In the sixth O site, O(2) is bonded to one Y(1), one Y(2), one Y(3), and one Re(1) atom to form distorted OY3Re trigonal pyramids that share corners with two equivalent O(7)Y3Re tetrahedra, corners with four equivalent O(6)Y4 tetrahedra, corners with four equivalent O(5)Y4 trigonal pyramids, and  an edgeedge with one O(7)Y3Re tetrahedra. In the seventh O site, O(3) is bonded in a 4-coordinate geometry to one Y(1), one Y(2), one Y(3), and one Re(1) atom. In the eighth O site, O(4) is bonded in a distorted trigonal planar geometry to one Y(1), one Y(3), and one Re(1) atom.