Sr2U4O11 crystallizes in the monoclinic Cm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a distorted hexagonal planar geometry to one O(11), one O(2), one O(4), one O(7), and two equivalent O(3) atoms. In the second Sr site, Sr(2) is bonded in a 7-coordinate geometry to one O(1), one O(6), one O(9), two equivalent O(10), and two equivalent O(2) atoms. There are four inequivalent U sites. In the first U site, U(1) is bonded in a body-centered cubic geometry to one O(1), one O(11), one O(4), one O(9), two equivalent O(5), and two equivalent O(8) atoms. In the second U site, U(2) is bonded in a body-centered cubic geometry to one O(10), one O(3), one O(5), one O(8), two equivalent O(4), and two equivalent O(9) atoms. In the third U site, U(3) is bonded in a distorted body-centered cubic geometry to one O(10), one O(2), one O(5), one O(7), two equivalent O(1), and two equivalent O(6) atoms. In the fourth U site, U(4) is bonded in a 7-coordinate geometry to one O(3), one O(6), one O(8), two equivalent O(11), and two equivalent O(7) atoms. There are eleven inequivalent O sites. In the first O site, O(1) is bonded to one Sr(2), one U(1), and two equivalent U(3) atoms to form OSrU3 tetrahedra that share  a cornercorner with one O(11)SrU3 tetrahedra,  a cornercorner with one O(4)SrU3 tetrahedra, corners with two equivalent O(1)SrU3 tetrahedra, corners with two equivalent O(7)SrU3 tetrahedra, corners with two equivalent O(8)U4 tetrahedra, corners with three equivalent O(6)SrU3 tetrahedra, corners with four equivalent O(10)Sr2U2 tetrahedra,  an edgeedge with one O(6)SrU3 tetrahedra,  an edgeedge with one O(9)SrU3 tetrahedra, edges with two equivalent O(2)Sr3U tetrahedra, and edges with two equivalent O(5)U4 tetrahedra. In the second O site, O(2) is bonded to one Sr(1), two equivalent Sr(2), and one U(3) atom to form OSr3U tetrahedra that share  a cornercorner with one O(11)SrU3 tetrahedra,  a cornercorner with one O(4)SrU3 tetrahedra,  a cornercorner with one O(5)U4 tetrahedra, corners with two equivalent O(3)Sr2U2 tetrahedra, corners with two equivalent O(2)Sr3U tetrahedra, corners with two equivalent O(9)SrU3 tetrahedra, corners with three equivalent O(10)Sr2U2 tetrahedra, corners with four equivalent O(6)SrU3 tetrahedra,  an edgeedge with one O(10)Sr2U2 tetrahedra,  an edgeedge with one O(7)SrU3 tetrahedra, and edges with two equivalent O(1)SrU3 tetrahedra. In the third O site, O(3) is bonded to two equivalent Sr(1), one U(2), and one U(4) atom to form OSr2U2 tetrahedra that share  a cornercorner with one O(10)Sr2U2 tetrahedra,  a cornercorner with one O(6)SrU3 tetrahedra,  a cornercorner with one O(5)U4 tetrahedra, corners with two equivalent O(3)Sr2U2 tetrahedra, corners with two equivalent O(2)Sr3U tetrahedra, corners with two equivalent O(9)SrU3 tetrahedra, corners with four equivalent O(11)SrU3 tetrahedra,  an edgeedge with one O(8)U4 tetrahedra, edges with two equivalent O(4)SrU3 tetrahedra, and edges with two equivalent O(7)SrU3 tetrahedra. In the fourth O site, O(4) is bonded to one Sr(1), one U(1), and two equivalent U(2) atoms to form OSrU3 tetrahedra that share  a cornercorner with one O(2)Sr3U tetrahedra,  a cornercorner with one O(1)SrU3 tetrahedra,  a cornercorner with one O(7)SrU3 tetrahedra, corners with two equivalent O(10)Sr2U2 tetrahedra, corners with two equivalent O(4)SrU3 tetrahedra, corners with three equivalent O(9)SrU3 tetrahedra, corners with four equivalent O(8)U4 tetrahedra,  an edgeedge with one O(11)SrU3 tetrahedra,  an edgeedge with one O(9)SrU3 tetrahedra, edges with two equivalent O(3)Sr2U2 tetrahedra, and edges with two equivalent O(5)U4 tetrahedra. In the fifth O site, O(5) is bonded to one U(2), one U(3), and two equivalent U(1) atoms to form OU4 tetrahedra that share  a cornercorner with one O(3)Sr2U2 tetrahedra,  a cornercorner with one O(2)Sr3U tetrahedra,  a cornercorner with one O(7)SrU3 tetrahedra, corners with two equivalent O(11)SrU3 tetrahedra, corners with two equivalent O(6)SrU3 tetrahedra, corners with two equivalent O(5)U4 tetrahedra, corners with three equivalent O(8)U4 tetrahedra, corners with four equivalent O(9)SrU3 tetrahedra,  an edgeedge with one O(10)Sr2U2 tetrahedra,  an edgeedge with one O(8)U4 tetrahedra, edges with two equivalent O(1)SrU3 tetrahedra, and edges with two equivalent O(4)SrU3 tetrahedra. In the sixth O site, O(6) is bonded to one Sr(2), one U(4), and two equivalent U(3) atoms to form OSrU3 tetrahedra that share  a cornercorner with one O(3)Sr2U2 tetrahedra,  a cornercorner with one O(9)SrU3 tetrahedra,  a cornercorner with one O(8)U4 tetrahedra, corners with two equivalent O(11)SrU3 tetrahedra, corners with two equivalent O(6)SrU3 tetrahedra, corners with two equivalent O(5)U4 tetrahedra, corners with three equivalent O(1)SrU3 tetrahedra, corners with four equivalent O(2)Sr3U tetrahedra,  an edgeedge with one O(1)SrU3 tetrahedra, edges with two equivalent O(10)Sr2U2 tetrahedra, and edges with two equivalent O(7)SrU3 tetrahedra. In the seventh O site, O(7) is bonded to one Sr(1), one U(3), and two equivalent U(4) atoms to form OSrU3 tetrahedra that share  a cornercorner with one O(10)Sr2U2 tetrahedra,  a cornercorner with one O(4)SrU3 tetrahedra,  a cornercorner with one O(5)U4 tetrahedra, corners with two equivalent O(1)SrU3 tetrahedra, corners with two equivalent O(7)SrU3 tetrahedra, corners with two equivalent O(8)U4 tetrahedra, corners with three equivalent O(11)SrU3 tetrahedra,  an edgeedge with one O(2)Sr3U tetrahedra,  an edgeedge with one O(11)SrU3 tetrahedra, edges with two equivalent O(3)Sr2U2 tetrahedra, and edges with two equivalent O(6)SrU3 tetrahedra. In the eighth O site, O(8) is bonded to one U(2), one U(4), and two equivalent U(1) atoms to form OU4 tetrahedra that share  a cornercorner with one O(10)Sr2U2 tetrahedra,  a cornercorner with one O(6)SrU3 tetrahedra, corners with two equivalent O(1)SrU3 tetrahedra, corners with two equivalent O(7)SrU3 tetrahedra, corners with two equivalent O(8)U4 tetrahedra, corners with three equivalent O(5)U4 tetrahedra, corners with four equivalent O(4)SrU3 tetrahedra,  an edgeedge with one O(3)Sr2U2 tetrahedra,  an edgeedge with one O(5)U4 tetrahedra, edges with two equivalent O(11)SrU3 tetrahedra, and edges with two equivalent O(9)SrU3 tetrahedra. In the ninth O site, O(9) is bonded to one Sr(2), one U(1), and two equivalent U(2) atoms to form OSrU3 tetrahedra that share  a cornercorner with one O(11)SrU3 tetrahedra,  a cornercorner with one O(6)SrU3 tetrahedra, corners with two equivalent O(3)Sr2U2 tetrahedra, corners with two equivalent O(2)Sr3U tetrahedra, corners with two equivalent O(9)SrU3 tetrahedra, corners with three equivalent O(4)SrU3 tetrahedra, corners with four equivalent O(5)U4 tetrahedra,  an edgeedge with one O(1)SrU3 tetrahedra,  an edgeedge with one O(4)SrU3 tetrahedra, edges with two equivalent O(10)Sr2U2 tetrahedra, and edges with two equivalent O(8)U4 tetrahedra. In the tenth O site, O(10) is bonded to two equivalent Sr(2), one U(2), and one U(3) atom to form OSr2U2 tetrahedra that share  a cornercorner with one O(3)Sr2U2 tetrahedra,  a cornercorner with one O(7)SrU3 tetrahedra,  a cornercorner with one O(8)U4 tetrahedra, corners with two equivalent O(10)Sr2U2 tetrahedra, corners with two equivalent O(4)SrU3 tetrahedra, corners with three equivalent O(2)Sr3U tetrahedra, corners with four equivalent O(1)SrU3 tetrahedra,  an edgeedge with one O(2)Sr3U tetrahedra,  an edgeedge with one O(5)U4 tetrahedra, edges with two equivalent O(6)SrU3 tetrahedra, and edges with two equivalent O(9)SrU3 tetrahedra. In the eleventh O site, O(11) is bonded to one Sr(1), one U(1), and two equivalent U(4) atoms to form OSrU3 tetrahedra that share  a cornercorner with one O(2)Sr3U tetrahedra,  a cornercorner with one O(1)SrU3 tetrahedra,  a cornercorner with one O(9)SrU3 tetrahedra, corners with two equivalent O(11)SrU3 tetrahedra, corners with two equivalent O(6)SrU3 tetrahedra, corners with two equivalent O(5)U4 tetrahedra, corners with three equivalent O(7)SrU3 tetrahedra, corners with four equivalent O(3)Sr2U2 tetrahedra,  an edgeedge with one O(4)SrU3 tetrahedra,  an edgeedge with one O(7)SrU3 tetrahedra, and edges with two equivalent O(8)U4 tetrahedra.
Sr2U4O11 crystallizes in the monoclinic Cm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a distorted hexagonal planar geometry to one O(11), one O(2), one O(4), one O(7), and two equivalent O(3) atoms. The Sr(1)-O(11) bond length is 2.47 Å. The Sr(1)-O(2) bond length is 2.47 Å. The Sr(1)-O(4) bond length is 2.52 Å. The Sr(1)-O(7) bond length is 2.43 Å. Both Sr(1)-O(3) bond lengths are 2.41 Å. In the second Sr site, Sr(2) is bonded in a 7-coordinate geometry to one O(1), one O(6), one O(9), two equivalent O(10), and two equivalent O(2) atoms. The Sr(2)-O(1) bond length is 2.60 Å. The Sr(2)-O(6) bond length is 2.60 Å. The Sr(2)-O(9) bond length is 2.44 Å. Both Sr(2)-O(10) bond lengths are 2.54 Å. Both Sr(2)-O(2) bond lengths are 2.51 Å. There are four inequivalent U sites. In the first U site, U(1) is bonded in a body-centered cubic geometry to one O(1), one O(11), one O(4), one O(9), two equivalent O(5), and two equivalent O(8) atoms. The U(1)-O(1) bond length is 2.28 Å. The U(1)-O(11) bond length is 2.39 Å. The U(1)-O(4) bond length is 2.27 Å. The U(1)-O(9) bond length is 2.33 Å. Both U(1)-O(5) bond lengths are 2.28 Å. Both U(1)-O(8) bond lengths are 2.36 Å. In the second U site, U(2) is bonded in a body-centered cubic geometry to one O(10), one O(3), one O(5), one O(8), two equivalent O(4), and two equivalent O(9) atoms. The U(2)-O(10) bond length is 2.19 Å. The U(2)-O(3) bond length is 2.23 Å. The U(2)-O(5) bond length is 2.44 Å. The U(2)-O(8) bond length is 2.52 Å. Both U(2)-O(4) bond lengths are 2.32 Å. Both U(2)-O(9) bond lengths are 2.36 Å. In the third U site, U(3) is bonded in a distorted body-centered cubic geometry to one O(10), one O(2), one O(5), one O(7), two equivalent O(1), and two equivalent O(6) atoms. The U(3)-O(10) bond length is 2.26 Å. The U(3)-O(2) bond length is 2.12 Å. The U(3)-O(5) bond length is 2.50 Å. The U(3)-O(7) bond length is 2.42 Å. Both U(3)-O(1) bond lengths are 2.31 Å. Both U(3)-O(6) bond lengths are 2.44 Å. In the fourth U site, U(4) is bonded in a 7-coordinate geometry to one O(3), one O(6), one O(8), two equivalent O(11), and two equivalent O(7) atoms. The U(4)-O(3) bond length is 2.24 Å. The U(4)-O(6) bond length is 2.21 Å. The U(4)-O(8) bond length is 2.27 Å. Both U(4)-O(11) bond lengths are 2.39 Å. Both U(4)-O(7) bond lengths are 2.25 Å. There are eleven inequivalent O sites. In the first O site, O(1) is bonded to one Sr(2), one U(1), and two equivalent U(3) atoms to form OSrU3 tetrahedra that share  a cornercorner with one O(11)SrU3 tetrahedra,  a cornercorner with one O(4)SrU3 tetrahedra, corners with two equivalent O(1)SrU3 tetrahedra, corners with two equivalent O(7)SrU3 tetrahedra, corners with two equivalent O(8)U4 tetrahedra, corners with three equivalent O(6)SrU3 tetrahedra, corners with four equivalent O(10)Sr2U2 tetrahedra,  an edgeedge with one O(6)SrU3 tetrahedra,  an edgeedge with one O(9)SrU3 tetrahedra, edges with two equivalent O(2)Sr3U tetrahedra, and edges with two equivalent O(5)U4 tetrahedra. In the second O site, O(2) is bonded to one Sr(1), two equivalent Sr(2), and one U(3) atom to form OSr3U tetrahedra that share  a cornercorner with one O(11)SrU3 tetrahedra,  a cornercorner with one O(4)SrU3 tetrahedra,  a cornercorner with one O(5)U4 tetrahedra, corners with two equivalent O(3)Sr2U2 tetrahedra, corners with two equivalent O(2)Sr3U tetrahedra, corners with two equivalent O(9)SrU3 tetrahedra, corners with three equivalent O(10)Sr2U2 tetrahedra, corners with four equivalent O(6)SrU3 tetrahedra,  an edgeedge with one O(10)Sr2U2 tetrahedra,  an edgeedge with one O(7)SrU3 tetrahedra, and edges with two equivalent O(1)SrU3 tetrahedra. In the third O site, O(3) is bonded to two equivalent Sr(1), one U(2), and one U(4) atom to form OSr2U2 tetrahedra that share  a cornercorner with one O(10)Sr2U2 tetrahedra,  a cornercorner with one O(6)SrU3 tetrahedra,  a cornercorner with one O(5)U4 tetrahedra, corners with two equivalent O(3)Sr2U2 tetrahedra, corners with two equivalent O(2)Sr3U tetrahedra, corners with two equivalent O(9)SrU3 tetrahedra, corners with four equivalent O(11)SrU3 tetrahedra,  an edgeedge with one O(8)U4 tetrahedra, edges with two equivalent O(4)SrU3 tetrahedra, and edges with two equivalent O(7)SrU3 tetrahedra. In the fourth O site, O(4) is bonded to one Sr(1), one U(1), and two equivalent U(2) atoms to form OSrU3 tetrahedra that share  a cornercorner with one O(2)Sr3U tetrahedra,  a cornercorner with one O(1)SrU3 tetrahedra,  a cornercorner with one O(7)SrU3 tetrahedra, corners with two equivalent O(10)Sr2U2 tetrahedra, corners with two equivalent O(4)SrU3 tetrahedra, corners with three equivalent O(9)SrU3 tetrahedra, corners with four equivalent O(8)U4 tetrahedra,  an edgeedge with one O(11)SrU3 tetrahedra,  an edgeedge with one O(9)SrU3 tetrahedra, edges with two equivalent O(3)Sr2U2 tetrahedra, and edges with two equivalent O(5)U4 tetrahedra. In the fifth O site, O(5) is bonded to one U(2), one U(3), and two equivalent U(1) atoms to form OU4 tetrahedra that share  a cornercorner with one O(3)Sr2U2 tetrahedra,  a cornercorner with one O(2)Sr3U tetrahedra,  a cornercorner with one O(7)SrU3 tetrahedra, corners with two equivalent O(11)SrU3 tetrahedra, corners with two equivalent O(6)SrU3 tetrahedra, corners with two equivalent O(5)U4 tetrahedra, corners with three equivalent O(8)U4 tetrahedra, corners with four equivalent O(9)SrU3 tetrahedra,  an edgeedge with one O(10)Sr2U2 tetrahedra,  an edgeedge with one O(8)U4 tetrahedra, edges with two equivalent O(1)SrU3 tetrahedra, and edges with two equivalent O(4)SrU3 tetrahedra. In the sixth O site, O(6) is bonded to one Sr(2), one U(4), and two equivalent U(3) atoms to form OSrU3 tetrahedra that share  a cornercorner with one O(3)Sr2U2 tetrahedra,  a cornercorner with one O(9)SrU3 tetrahedra,  a cornercorner with one O(8)U4 tetrahedra, corners with two equivalent O(11)SrU3 tetrahedra, corners with two equivalent O(6)SrU3 tetrahedra, corners with two equivalent O(5)U4 tetrahedra, corners with three equivalent O(1)SrU3 tetrahedra, corners with four equivalent O(2)Sr3U tetrahedra,  an edgeedge with one O(1)SrU3 tetrahedra, edges with two equivalent O(10)Sr2U2 tetrahedra, and edges with two equivalent O(7)SrU3 tetrahedra. In the seventh O site, O(7) is bonded to one Sr(1), one U(3), and two equivalent U(4) atoms to form OSrU3 tetrahedra that share  a cornercorner with one O(10)Sr2U2 tetrahedra,  a cornercorner with one O(4)SrU3 tetrahedra,  a cornercorner with one O(5)U4 tetrahedra, corners with two equivalent O(1)SrU3 tetrahedra, corners with two equivalent O(7)SrU3 tetrahedra, corners with two equivalent O(8)U4 tetrahedra, corners with three equivalent O(11)SrU3 tetrahedra,  an edgeedge with one O(2)Sr3U tetrahedra,  an edgeedge with one O(11)SrU3 tetrahedra, edges with two equivalent O(3)Sr2U2 tetrahedra, and edges with two equivalent O(6)SrU3 tetrahedra. In the eighth O site, O(8) is bonded to one U(2), one U(4), and two equivalent U(1) atoms to form OU4 tetrahedra that share  a cornercorner with one O(10)Sr2U2 tetrahedra,  a cornercorner with one O(6)SrU3 tetrahedra, corners with two equivalent O(1)SrU3 tetrahedra, corners with two equivalent O(7)SrU3 tetrahedra, corners with two equivalent O(8)U4 tetrahedra, corners with three equivalent O(5)U4 tetrahedra, corners with four equivalent O(4)SrU3 tetrahedra,  an edgeedge with one O(3)Sr2U2 tetrahedra,  an edgeedge with one O(5)U4 tetrahedra, edges with two equivalent O(11)SrU3 tetrahedra, and edges with two equivalent O(9)SrU3 tetrahedra. In the ninth O site, O(9) is bonded to one Sr(2), one U(1), and two equivalent U(2) atoms to form OSrU3 tetrahedra that share  a cornercorner with one O(11)SrU3 tetrahedra,  a cornercorner with one O(6)SrU3 tetrahedra, corners with two equivalent O(3)Sr2U2 tetrahedra, corners with two equivalent O(2)Sr3U tetrahedra, corners with two equivalent O(9)SrU3 tetrahedra, corners with three equivalent O(4)SrU3 tetrahedra, corners with four equivalent O(5)U4 tetrahedra,  an edgeedge with one O(1)SrU3 tetrahedra,  an edgeedge with one O(4)SrU3 tetrahedra, edges with two equivalent O(10)Sr2U2 tetrahedra, and edges with two equivalent O(8)U4 tetrahedra. In the tenth O site, O(10) is bonded to two equivalent Sr(2), one U(2), and one U(3) atom to form OSr2U2 tetrahedra that share  a cornercorner with one O(3)Sr2U2 tetrahedra,  a cornercorner with one O(7)SrU3 tetrahedra,  a cornercorner with one O(8)U4 tetrahedra, corners with two equivalent O(10)Sr2U2 tetrahedra, corners with two equivalent O(4)SrU3 tetrahedra, corners with three equivalent O(2)Sr3U tetrahedra, corners with four equivalent O(1)SrU3 tetrahedra,  an edgeedge with one O(2)Sr3U tetrahedra,  an edgeedge with one O(5)U4 tetrahedra, edges with two equivalent O(6)SrU3 tetrahedra, and edges with two equivalent O(9)SrU3 tetrahedra. In the eleventh O site, O(11) is bonded to one Sr(1), one U(1), and two equivalent U(4) atoms to form OSrU3 tetrahedra that share  a cornercorner with one O(2)Sr3U tetrahedra,  a cornercorner with one O(1)SrU3 tetrahedra,  a cornercorner with one O(9)SrU3 tetrahedra, corners with two equivalent O(11)SrU3 tetrahedra, corners with two equivalent O(6)SrU3 tetrahedra, corners with two equivalent O(5)U4 tetrahedra, corners with three equivalent O(7)SrU3 tetrahedra, corners with four equivalent O(3)Sr2U2 tetrahedra,  an edgeedge with one O(4)SrU3 tetrahedra,  an edgeedge with one O(7)SrU3 tetrahedra, and edges with two equivalent O(8)U4 tetrahedra.