Y2Hg2O5 crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form YO6 octahedra that share corners with five equivalent Y(2)O6 octahedra,  a cornercorner with one Hg(1)O5 square pyramid, corners with two equivalent Hg(2)O5 square pyramids, edges with two equivalent Y(1)O6 octahedra, edges with two equivalent Hg(1)O5 square pyramids, and edges with two equivalent Hg(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 0-55°. In the second Y site, Y(2) is bonded to one O(3), one O(4), two equivalent O(2), and two equivalent O(5) atoms to form YO6 octahedra that share corners with five equivalent Y(1)O6 octahedra,  a cornercorner with one Hg(2)O5 square pyramid, corners with two equivalent Hg(1)O5 square pyramids, edges with two equivalent Y(2)O6 octahedra, edges with two equivalent Hg(1)O5 square pyramids, and edges with two equivalent Hg(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 0-55°. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded to one O(1), one O(2), one O(5), and two equivalent O(3) atoms to form distorted HgO5 square pyramids that share  a cornercorner with one Y(1)O6 octahedra, corners with two equivalent Y(2)O6 octahedra, corners with two equivalent Hg(1)O5 square pyramids, corners with two equivalent Hg(2)O5 square pyramids, edges with two equivalent Y(1)O6 octahedra, edges with two equivalent Y(2)O6 octahedra, and edges with two equivalent Hg(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 51-75°. In the second Hg site, Hg(2) is bonded to one O(1), one O(4), one O(5), and two equivalent O(3) atoms to form distorted HgO5 square pyramids that share  a cornercorner with one Y(2)O6 octahedra, corners with two equivalent Y(1)O6 octahedra, corners with two equivalent Hg(1)O5 square pyramids, corners with two equivalent Hg(2)O5 square pyramids, edges with two equivalent Y(1)O6 octahedra, edges with two equivalent Y(2)O6 octahedra, and edges with two equivalent Hg(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 50-75°. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Y(1), one Hg(1), and one Hg(2) atom to form OY2Hg2 tetrahedra that share corners with two equivalent O(3)Y2Hg4 octahedra, corners with two equivalent O(1)Y2Hg2 tetrahedra, corners with three equivalent O(2)Y3Hg trigonal pyramids, corners with three equivalent O(4)Y3Hg trigonal pyramids, edges with two equivalent O(3)Y2Hg4 octahedra,  an edgeedge with one O(5)Y2Hg2 tetrahedra, and  an edgeedge with one O(4)Y3Hg trigonal pyramid. The corner-sharing octahedral tilt angles range from 40-55°. In the second O site, O(2) is bonded to one Y(1), two equivalent Y(2), and one Hg(1) atom to form OY3Hg trigonal pyramids that share  a cornercorner with one O(3)Y2Hg4 octahedra, corners with three equivalent O(1)Y2Hg2 tetrahedra, corners with three equivalent O(5)Y2Hg2 tetrahedra, corners with two equivalent O(2)Y3Hg trigonal pyramids, corners with four equivalent O(4)Y3Hg trigonal pyramids, edges with two equivalent O(3)Y2Hg4 octahedra, and  an edgeedge with one O(5)Y2Hg2 tetrahedra. The corner-sharing octahedral tilt angles are 17°. In the third O site, O(3) is bonded to one Y(1), one Y(2), two equivalent Hg(1), and two equivalent Hg(2) atoms to form OY2Hg4 octahedra that share corners with two equivalent O(1)Y2Hg2 tetrahedra, corners with two equivalent O(5)Y2Hg2 tetrahedra,  a cornercorner with one O(2)Y3Hg trigonal pyramid,  a cornercorner with one O(4)Y3Hg trigonal pyramid, edges with two equivalent O(3)Y2Hg4 octahedra, edges with two equivalent O(1)Y2Hg2 tetrahedra, edges with two equivalent O(5)Y2Hg2 tetrahedra, edges with two equivalent O(2)Y3Hg trigonal pyramids, and edges with two equivalent O(4)Y3Hg trigonal pyramids. In the fourth O site, O(4) is bonded to one Y(2), two equivalent Y(1), and one Hg(2) atom to form OY3Hg trigonal pyramids that share  a cornercorner with one O(3)Y2Hg4 octahedra, corners with three equivalent O(1)Y2Hg2 tetrahedra, corners with three equivalent O(5)Y2Hg2 tetrahedra, corners with two equivalent O(4)Y3Hg trigonal pyramids, corners with four equivalent O(2)Y3Hg trigonal pyramids, edges with two equivalent O(3)Y2Hg4 octahedra, and  an edgeedge with one O(1)Y2Hg2 tetrahedra. The corner-sharing octahedral tilt angles are 17°. In the fifth O site, O(5) is bonded to two equivalent Y(2), one Hg(1), and one Hg(2) atom to form OY2Hg2 tetrahedra that share corners with two equivalent O(3)Y2Hg4 octahedra, corners with two equivalent O(5)Y2Hg2 tetrahedra, corners with three equivalent O(2)Y3Hg trigonal pyramids, corners with three equivalent O(4)Y3Hg trigonal pyramids, edges with two equivalent O(3)Y2Hg4 octahedra,  an edgeedge with one O(1)Y2Hg2 tetrahedra, and  an edgeedge with one O(2)Y3Hg trigonal pyramid. The corner-sharing octahedral tilt angles range from 41-55°.
Y2Hg2O5 crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form YO6 octahedra that share corners with five equivalent Y(2)O6 octahedra,  a cornercorner with one Hg(1)O5 square pyramid, corners with two equivalent Hg(2)O5 square pyramids, edges with two equivalent Y(1)O6 octahedra, edges with two equivalent Hg(1)O5 square pyramids, and edges with two equivalent Hg(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 0-55°. The Y(1)-O(2) bond length is 2.28 Å. The Y(1)-O(3) bond length is 2.49 Å. There is one shorter (2.26 Å) and one longer (2.28 Å) Y(1)-O(1) bond length. There is one shorter (2.34 Å) and one longer (2.35 Å) Y(1)-O(4) bond length. In the second Y site, Y(2) is bonded to one O(3), one O(4), two equivalent O(2), and two equivalent O(5) atoms to form YO6 octahedra that share corners with five equivalent Y(1)O6 octahedra,  a cornercorner with one Hg(2)O5 square pyramid, corners with two equivalent Hg(1)O5 square pyramids, edges with two equivalent Y(2)O6 octahedra, edges with two equivalent Hg(1)O5 square pyramids, and edges with two equivalent Hg(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 0-55°. The Y(2)-O(3) bond length is 2.49 Å. The Y(2)-O(4) bond length is 2.28 Å. There is one shorter (2.33 Å) and one longer (2.37 Å) Y(2)-O(2) bond length. There is one shorter (2.26 Å) and one longer (2.28 Å) Y(2)-O(5) bond length. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded to one O(1), one O(2), one O(5), and two equivalent O(3) atoms to form distorted HgO5 square pyramids that share  a cornercorner with one Y(1)O6 octahedra, corners with two equivalent Y(2)O6 octahedra, corners with two equivalent Hg(1)O5 square pyramids, corners with two equivalent Hg(2)O5 square pyramids, edges with two equivalent Y(1)O6 octahedra, edges with two equivalent Y(2)O6 octahedra, and edges with two equivalent Hg(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 51-75°. The Hg(1)-O(1) bond length is 2.36 Å. The Hg(1)-O(2) bond length is 2.31 Å. The Hg(1)-O(5) bond length is 2.25 Å. There is one shorter (2.41 Å) and one longer (2.61 Å) Hg(1)-O(3) bond length. In the second Hg site, Hg(2) is bonded to one O(1), one O(4), one O(5), and two equivalent O(3) atoms to form distorted HgO5 square pyramids that share  a cornercorner with one Y(2)O6 octahedra, corners with two equivalent Y(1)O6 octahedra, corners with two equivalent Hg(1)O5 square pyramids, corners with two equivalent Hg(2)O5 square pyramids, edges with two equivalent Y(1)O6 octahedra, edges with two equivalent Y(2)O6 octahedra, and edges with two equivalent Hg(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 50-75°. The Hg(2)-O(1) bond length is 2.24 Å. The Hg(2)-O(4) bond length is 2.31 Å. The Hg(2)-O(5) bond length is 2.37 Å. There is one shorter (2.41 Å) and one longer (2.60 Å) Hg(2)-O(3) bond length. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Y(1), one Hg(1), and one Hg(2) atom to form OY2Hg2 tetrahedra that share corners with two equivalent O(3)Y2Hg4 octahedra, corners with two equivalent O(1)Y2Hg2 tetrahedra, corners with three equivalent O(2)Y3Hg trigonal pyramids, corners with three equivalent O(4)Y3Hg trigonal pyramids, edges with two equivalent O(3)Y2Hg4 octahedra,  an edgeedge with one O(5)Y2Hg2 tetrahedra, and  an edgeedge with one O(4)Y3Hg trigonal pyramid. The corner-sharing octahedral tilt angles range from 40-55°. In the second O site, O(2) is bonded to one Y(1), two equivalent Y(2), and one Hg(1) atom to form OY3Hg trigonal pyramids that share  a cornercorner with one O(3)Y2Hg4 octahedra, corners with three equivalent O(1)Y2Hg2 tetrahedra, corners with three equivalent O(5)Y2Hg2 tetrahedra, corners with two equivalent O(2)Y3Hg trigonal pyramids, corners with four equivalent O(4)Y3Hg trigonal pyramids, edges with two equivalent O(3)Y2Hg4 octahedra, and  an edgeedge with one O(5)Y2Hg2 tetrahedra. The corner-sharing octahedral tilt angles are 17°. In the third O site, O(3) is bonded to one Y(1), one Y(2), two equivalent Hg(1), and two equivalent Hg(2) atoms to form OY2Hg4 octahedra that share corners with two equivalent O(1)Y2Hg2 tetrahedra, corners with two equivalent O(5)Y2Hg2 tetrahedra,  a cornercorner with one O(2)Y3Hg trigonal pyramid,  a cornercorner with one O(4)Y3Hg trigonal pyramid, edges with two equivalent O(3)Y2Hg4 octahedra, edges with two equivalent O(1)Y2Hg2 tetrahedra, edges with two equivalent O(5)Y2Hg2 tetrahedra, edges with two equivalent O(2)Y3Hg trigonal pyramids, and edges with two equivalent O(4)Y3Hg trigonal pyramids. In the fourth O site, O(4) is bonded to one Y(2), two equivalent Y(1), and one Hg(2) atom to form OY3Hg trigonal pyramids that share  a cornercorner with one O(3)Y2Hg4 octahedra, corners with three equivalent O(1)Y2Hg2 tetrahedra, corners with three equivalent O(5)Y2Hg2 tetrahedra, corners with two equivalent O(4)Y3Hg trigonal pyramids, corners with four equivalent O(2)Y3Hg trigonal pyramids, edges with two equivalent O(3)Y2Hg4 octahedra, and  an edgeedge with one O(1)Y2Hg2 tetrahedra. The corner-sharing octahedral tilt angles are 17°. In the fifth O site, O(5) is bonded to two equivalent Y(2), one Hg(1), and one Hg(2) atom to form OY2Hg2 tetrahedra that share corners with two equivalent O(3)Y2Hg4 octahedra, corners with two equivalent O(5)Y2Hg2 tetrahedra, corners with three equivalent O(2)Y3Hg trigonal pyramids, corners with three equivalent O(4)Y3Hg trigonal pyramids, edges with two equivalent O(3)Y2Hg4 octahedra,  an edgeedge with one O(1)Y2Hg2 tetrahedra, and  an edgeedge with one O(2)Y3Hg trigonal pyramid. The corner-sharing octahedral tilt angles range from 41-55°.