Y2MnSbO7 crystallizes in the orthorhombic Imma space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to two equivalent O(1), two equivalent O(2), and four equivalent O(4) atoms to form distorted YO8 hexagonal bipyramids that share edges with two equivalent Y(1)O8 hexagonal bipyramids, edges with two equivalent Mn(1)O6 octahedra, and edges with four equivalent Sb(1)O6 octahedra. In the second Y site, Y(2) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(3), and four equivalent O(4) atoms. Mn(1) is bonded to two equivalent O(3) and four equivalent O(4) atoms to form MnO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra, corners with four equivalent Sb(1)O6 octahedra, and edges with two equivalent Y(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 51-53°. Sb(1) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form SbO6 octahedra that share corners with two equivalent Sb(1)O6 octahedra, corners with four equivalent Mn(1)O6 octahedra, and edges with four equivalent Y(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 47-53°. There are four 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(3)Y2Mn2 tetrahedra, corners with two equivalent O(2)Y2Sb2 tetrahedra, corners with four equivalent O(1)Y4 tetrahedra, corners with eight equivalent O(4)Y2MnSb tetrahedra,  an edgeedge with one O(3)Y2Mn2 tetrahedra,  an edgeedge with one O(2)Y2Sb2 tetrahedra, and edges with four equivalent O(4)Y2MnSb tetrahedra. In the second O site, O(2) is bonded to two equivalent Y(1) and two equivalent Sb(1) atoms to form distorted OY2Sb2 tetrahedra that share corners with two equivalent O(1)Y4 tetrahedra, corners with four equivalent O(2)Y2Sb2 tetrahedra, corners with eight equivalent O(4)Y2MnSb tetrahedra,  an edgeedge with one O(1)Y4 tetrahedra, and edges with four equivalent O(4)Y2MnSb tetrahedra. In the third O site, O(3) is bonded to two equivalent Y(2) and two equivalent Mn(1) atoms to form distorted OY2Mn2 tetrahedra that share corners with two equivalent O(1)Y4 tetrahedra, corners with four equivalent O(3)Y2Mn2 tetrahedra, corners with eight equivalent O(4)Y2MnSb tetrahedra,  an edgeedge with one O(1)Y4 tetrahedra, and edges with four equivalent O(4)Y2MnSb tetrahedra. In the fourth O site, O(4) is bonded to one Y(1), one Y(2), one Mn(1), and one Sb(1) atom to form distorted OY2MnSb tetrahedra that share corners with two equivalent O(3)Y2Mn2 tetrahedra, corners with two equivalent O(2)Y2Sb2 tetrahedra, corners with two equivalent O(1)Y4 tetrahedra, corners with eight equivalent O(4)Y2MnSb tetrahedra,  an edgeedge with one O(3)Y2Mn2 tetrahedra,  an edgeedge with one O(2)Y2Sb2 tetrahedra,  an edgeedge with one O(1)Y4 tetrahedra, and edges with two equivalent O(4)Y2MnSb tetrahedra.
Y2MnSbO7 crystallizes in the orthorhombic Imma space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to two equivalent O(1), two equivalent O(2), and four equivalent O(4) atoms to form distorted YO8 hexagonal bipyramids that share edges with two equivalent Y(1)O8 hexagonal bipyramids, edges with two equivalent Mn(1)O6 octahedra, and edges with four equivalent Sb(1)O6 octahedra. Both Y(1)-O(1) bond lengths are 2.22 Å. Both Y(1)-O(2) bond lengths are 2.52 Å. All Y(1)-O(4) bond lengths are 2.50 Å. In the second Y site, Y(2) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(3), and four equivalent O(4) atoms. Both Y(2)-O(1) bond lengths are 2.26 Å. Both Y(2)-O(3) bond lengths are 2.56 Å. All Y(2)-O(4) bond lengths are 2.47 Å. Mn(1) is bonded to two equivalent O(3) and four equivalent O(4) atoms to form MnO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra, corners with four equivalent Sb(1)O6 octahedra, and edges with two equivalent Y(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 51-53°. Both Mn(1)-O(3) bond lengths are 1.98 Å. All Mn(1)-O(4) bond lengths are 2.10 Å. Sb(1) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form SbO6 octahedra that share corners with two equivalent Sb(1)O6 octahedra, corners with four equivalent Mn(1)O6 octahedra, and edges with four equivalent Y(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 47-53°. Both Sb(1)-O(2) bond lengths are 2.04 Å. All Sb(1)-O(4) bond lengths are 1.99 Å. There are four 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(3)Y2Mn2 tetrahedra, corners with two equivalent O(2)Y2Sb2 tetrahedra, corners with four equivalent O(1)Y4 tetrahedra, corners with eight equivalent O(4)Y2MnSb tetrahedra,  an edgeedge with one O(3)Y2Mn2 tetrahedra,  an edgeedge with one O(2)Y2Sb2 tetrahedra, and edges with four equivalent O(4)Y2MnSb tetrahedra. In the second O site, O(2) is bonded to two equivalent Y(1) and two equivalent Sb(1) atoms to form distorted OY2Sb2 tetrahedra that share corners with two equivalent O(1)Y4 tetrahedra, corners with four equivalent O(2)Y2Sb2 tetrahedra, corners with eight equivalent O(4)Y2MnSb tetrahedra,  an edgeedge with one O(1)Y4 tetrahedra, and edges with four equivalent O(4)Y2MnSb tetrahedra. In the third O site, O(3) is bonded to two equivalent Y(2) and two equivalent Mn(1) atoms to form distorted OY2Mn2 tetrahedra that share corners with two equivalent O(1)Y4 tetrahedra, corners with four equivalent O(3)Y2Mn2 tetrahedra, corners with eight equivalent O(4)Y2MnSb tetrahedra,  an edgeedge with one O(1)Y4 tetrahedra, and edges with four equivalent O(4)Y2MnSb tetrahedra. In the fourth O site, O(4) is bonded to one Y(1), one Y(2), one Mn(1), and one Sb(1) atom to form distorted OY2MnSb tetrahedra that share corners with two equivalent O(3)Y2Mn2 tetrahedra, corners with two equivalent O(2)Y2Sb2 tetrahedra, corners with two equivalent O(1)Y4 tetrahedra, corners with eight equivalent O(4)Y2MnSb tetrahedra,  an edgeedge with one O(3)Y2Mn2 tetrahedra,  an edgeedge with one O(2)Y2Sb2 tetrahedra,  an edgeedge with one O(1)Y4 tetrahedra, and edges with two equivalent O(4)Y2MnSb tetrahedra.