U7Cd3O20 is Fluorite-derived structured and crystallizes in the monoclinic C2/m space group. There are four inequivalent U sites. In the first U site, U(1) is bonded in a 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 U site, U(2) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(3), two equivalent O(4), and two equivalent O(6) atoms. In the third U site, U(3) is bonded in a body-centered cubic geometry to two equivalent O(2), two equivalent O(4), and four equivalent O(3) atoms. In the fourth U site, U(4) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(6), and four equivalent O(5) atoms. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in a body-centered cubic geometry to two equivalent O(2), two equivalent O(4), and four equivalent O(1) atoms. In the second Cd site, Cd(2) is bonded in a body-centered cubic geometry to two equivalent O(3), two equivalent O(5), and four equivalent O(6) atoms. There are six inequivalent O sites. In the first O site, O(6) is bonded to one U(2), one U(4), and two equivalent Cd(2) atoms to form OU2Cd2 tetrahedra that share corners with two equivalent O(1)U3Cd tetrahedra, corners with two equivalent O(4)U3Cd tetrahedra, corners with four equivalent O(6)U2Cd2 tetrahedra, corners with four equivalent O(3)U3Cd tetrahedra, corners with four equivalent O(5)U3Cd tetrahedra,  an edgeedge with one O(1)U3Cd tetrahedra,  an edgeedge with one O(3)U3Cd tetrahedra, edges with two equivalent O(6)U2Cd2 tetrahedra, and edges with two equivalent O(5)U3Cd tetrahedra. In the second O site, O(1) is bonded to one U(1), one U(2), one U(4), and one Cd(1) atom to form OU3Cd tetrahedra that share corners with two equivalent O(6)U2Cd2 tetrahedra, corners with two equivalent O(2)U3Cd tetrahedra, corners with two equivalent O(3)U3Cd tetrahedra, corners with two equivalent O(4)U3Cd tetrahedra, corners with four equivalent O(1)U3Cd tetrahedra, corners with four equivalent O(5)U3Cd tetrahedra,  an edgeedge with one O(6)U2Cd2 tetrahedra,  an edgeedge with one O(1)U3Cd tetrahedra,  an edgeedge with one O(2)U3Cd tetrahedra,  an edgeedge with one O(3)U3Cd tetrahedra,  an edgeedge with one O(4)U3Cd tetrahedra, and  an edgeedge with one O(5)U3Cd tetrahedra. In the third O site, O(2) is bonded to one U(3), two equivalent U(1), and one Cd(1) atom to form a mixture of corner and edge-sharing OU3Cd tetrahedra. In the fourth O site, O(3) is bonded to one U(1), one U(2), one U(3), and one Cd(2) atom to form OU3Cd tetrahedra that share corners with two equivalent O(1)U3Cd tetrahedra, corners with two equivalent O(2)U3Cd tetrahedra, corners with two equivalent O(4)U3Cd tetrahedra, corners with two equivalent O(5)U3Cd tetrahedra, corners with four equivalent O(6)U2Cd2 tetrahedra, corners with four equivalent O(3)U3Cd tetrahedra,  an edgeedge with one O(6)U2Cd2 tetrahedra,  an edgeedge with one O(1)U3Cd tetrahedra,  an edgeedge with one O(2)U3Cd tetrahedra,  an edgeedge with one O(3)U3Cd tetrahedra,  an edgeedge with one O(4)U3Cd tetrahedra, and  an edgeedge with one O(5)U3Cd tetrahedra. In the fifth O site, O(4) is bonded to one U(3), two equivalent U(2), and one Cd(1) atom to form OU3Cd tetrahedra that share corners with two equivalent O(2)U3Cd tetrahedra, corners with two equivalent O(4)U3Cd tetrahedra, corners with four equivalent O(6)U2Cd2 tetrahedra, corners with four equivalent O(1)U3Cd tetrahedra, corners with four equivalent O(3)U3Cd tetrahedra,  an edgeedge with one O(2)U3Cd tetrahedra,  an edgeedge with one O(4)U3Cd tetrahedra, edges with two equivalent O(1)U3Cd tetrahedra, and edges with two equivalent O(3)U3Cd tetrahedra. In the sixth O site, O(5) is bonded to one U(1), two equivalent U(4), and one Cd(2) atom to form OU3Cd tetrahedra that share corners with two equivalent O(2)U3Cd tetrahedra, corners with two equivalent O(3)U3Cd tetrahedra, corners with four equivalent O(6)U2Cd2 tetrahedra, corners with four equivalent O(1)U3Cd tetrahedra, corners with four equivalent O(5)U3Cd tetrahedra,  an edgeedge with one O(1)U3Cd tetrahedra,  an edgeedge with one O(3)U3Cd tetrahedra, edges with two equivalent O(6)U2Cd2 tetrahedra, and edges with two equivalent O(5)U3Cd tetrahedra.
U7Cd3O20 is Fluorite-derived structured and crystallizes in the monoclinic C2/m space group. There are four inequivalent U sites. In the first U site, U(1) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. Both U(1)-O(1) bond lengths are 2.28 Å. Both U(1)-O(2) bond lengths are 2.30 Å. Both U(1)-O(3) bond lengths are 2.28 Å. Both U(1)-O(5) bond lengths are 2.27 Å. In the second U site, U(2) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(3), two equivalent O(4), and two equivalent O(6) atoms. Both U(2)-O(1) bond lengths are 2.31 Å. Both U(2)-O(3) bond lengths are 2.32 Å. Both U(2)-O(4) bond lengths are 2.31 Å. Both U(2)-O(6) bond lengths are 2.26 Å. In the third U site, U(3) is bonded in a body-centered cubic geometry to two equivalent O(2), two equivalent O(4), and four equivalent O(3) atoms. Both U(3)-O(2) bond lengths are 2.29 Å. Both U(3)-O(4) bond lengths are 2.30 Å. All U(3)-O(3) bond lengths are 2.29 Å. In the fourth U site, U(4) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(6), and four equivalent O(5) atoms. Both U(4)-O(1) bond lengths are 2.32 Å. Both U(4)-O(6) bond lengths are 2.20 Å. All U(4)-O(5) bond lengths are 2.30 Å. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in a body-centered cubic geometry to two equivalent O(2), two equivalent O(4), and four equivalent O(1) atoms. Both Cd(1)-O(2) bond lengths are 2.42 Å. Both Cd(1)-O(4) bond lengths are 2.41 Å. All Cd(1)-O(1) bond lengths are 2.39 Å. In the second Cd site, Cd(2) is bonded in a body-centered cubic geometry to two equivalent O(3), two equivalent O(5), and four equivalent O(6) atoms. Both Cd(2)-O(3) bond lengths are 2.45 Å. Both Cd(2)-O(5) bond lengths are 2.44 Å. There are two shorter (2.40 Å) and two longer (2.41 Å) Cd(2)-O(6) bond lengths. There are six inequivalent O sites. In the first O site, O(6) is bonded to one U(2), one U(4), and two equivalent Cd(2) atoms to form OU2Cd2 tetrahedra that share corners with two equivalent O(1)U3Cd tetrahedra, corners with two equivalent O(4)U3Cd tetrahedra, corners with four equivalent O(6)U2Cd2 tetrahedra, corners with four equivalent O(3)U3Cd tetrahedra, corners with four equivalent O(5)U3Cd tetrahedra,  an edgeedge with one O(1)U3Cd tetrahedra,  an edgeedge with one O(3)U3Cd tetrahedra, edges with two equivalent O(6)U2Cd2 tetrahedra, and edges with two equivalent O(5)U3Cd tetrahedra. In the second O site, O(1) is bonded to one U(1), one U(2), one U(4), and one Cd(1) atom to form OU3Cd tetrahedra that share corners with two equivalent O(6)U2Cd2 tetrahedra, corners with two equivalent O(2)U3Cd tetrahedra, corners with two equivalent O(3)U3Cd tetrahedra, corners with two equivalent O(4)U3Cd tetrahedra, corners with four equivalent O(1)U3Cd tetrahedra, corners with four equivalent O(5)U3Cd tetrahedra,  an edgeedge with one O(6)U2Cd2 tetrahedra,  an edgeedge with one O(1)U3Cd tetrahedra,  an edgeedge with one O(2)U3Cd tetrahedra,  an edgeedge with one O(3)U3Cd tetrahedra,  an edgeedge with one O(4)U3Cd tetrahedra, and  an edgeedge with one O(5)U3Cd tetrahedra. In the third O site, O(2) is bonded to one U(3), two equivalent U(1), and one Cd(1) atom to form a mixture of corner and edge-sharing OU3Cd tetrahedra. In the fourth O site, O(3) is bonded to one U(1), one U(2), one U(3), and one Cd(2) atom to form OU3Cd tetrahedra that share corners with two equivalent O(1)U3Cd tetrahedra, corners with two equivalent O(2)U3Cd tetrahedra, corners with two equivalent O(4)U3Cd tetrahedra, corners with two equivalent O(5)U3Cd tetrahedra, corners with four equivalent O(6)U2Cd2 tetrahedra, corners with four equivalent O(3)U3Cd tetrahedra,  an edgeedge with one O(6)U2Cd2 tetrahedra,  an edgeedge with one O(1)U3Cd tetrahedra,  an edgeedge with one O(2)U3Cd tetrahedra,  an edgeedge with one O(3)U3Cd tetrahedra,  an edgeedge with one O(4)U3Cd tetrahedra, and  an edgeedge with one O(5)U3Cd tetrahedra. In the fifth O site, O(4) is bonded to one U(3), two equivalent U(2), and one Cd(1) atom to form OU3Cd tetrahedra that share corners with two equivalent O(2)U3Cd tetrahedra, corners with two equivalent O(4)U3Cd tetrahedra, corners with four equivalent O(6)U2Cd2 tetrahedra, corners with four equivalent O(1)U3Cd tetrahedra, corners with four equivalent O(3)U3Cd tetrahedra,  an edgeedge with one O(2)U3Cd tetrahedra,  an edgeedge with one O(4)U3Cd tetrahedra, edges with two equivalent O(1)U3Cd tetrahedra, and edges with two equivalent O(3)U3Cd tetrahedra. In the sixth O site, O(5) is bonded to one U(1), two equivalent U(4), and one Cd(2) atom to form OU3Cd tetrahedra that share corners with two equivalent O(2)U3Cd tetrahedra, corners with two equivalent O(3)U3Cd tetrahedra, corners with four equivalent O(6)U2Cd2 tetrahedra, corners with four equivalent O(1)U3Cd tetrahedra, corners with four equivalent O(5)U3Cd tetrahedra,  an edgeedge with one O(1)U3Cd tetrahedra,  an edgeedge with one O(3)U3Cd tetrahedra, edges with two equivalent O(6)U2Cd2 tetrahedra, and edges with two equivalent O(5)U3Cd tetrahedra.