The compound described by Sr5U5O18 crystallizes in the triclinic P-1 space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one O(5), one O(7), one O(8), two equivalent O(1), and two equivalent O(4) atoms to form distorted SrO7 pentagonal bipyramids that share  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one U(2)O7 pentagonal bipyramid, edges with two equivalent Sr(1)O7 pentagonal bipyramids, and edges with two equivalent U(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 53°. In the second Sr site, Sr(2) is bonded in a distorted body-centered cubic geometry to one O(1), one O(4), one O(6), one O(7), one O(8), one O(9), and two equivalent O(3) atoms. In the third Sr site, Sr(3) is bonded in a distorted body-centered cubic geometry to two equivalent O(2), two equivalent O(3), two equivalent O(7), and two equivalent O(8) atoms. There are three inequivalent U sites. In the first U site, U(1) is bonded to two equivalent O(2), two equivalent O(8), and two equivalent O(9) atoms to form UO6 octahedra that share corners with two equivalent Sr(1)O7 pentagonal bipyramids and corners with two equivalent U(2)O7 pentagonal bipyramids. In the second U site, U(2) is bonded to one O(1), one O(2), one O(7), two equivalent O(5), and two equivalent O(6) atoms to form distorted UO7 pentagonal bipyramids that share  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one Sr(1)O7 pentagonal bipyramid, edges with two equivalent Sr(1)O7 pentagonal bipyramids, and edges with two equivalent U(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 38°. In the third U site, U(3) is bonded in a 7-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(9) atoms. There are nine inequivalent O sites. In the first O site, O(1) is bonded to one Sr(2), two equivalent Sr(1), and one U(2) atom to form distorted OSr3U tetrahedra that share  a cornercorner with one O(8)Sr3U tetrahedra, corners with two equivalent O(3)Sr3U tetrahedra, corners with three equivalent O(4)Sr3U tetrahedra, corners with four equivalent O(7)Sr3U tetrahedra,  a cornercorner with one O(6)SrU3 trigonal pyramid,  a cornercorner with one O(9)SrU3 trigonal pyramid, corners with two equivalent O(5)SrU3 trigonal pyramids,  an edgeedge with one O(1)Sr3U tetrahedra,  an edgeedge with one O(4)Sr3U tetrahedra,  an edgeedge with one O(8)Sr3U tetrahedra,  an edgeedge with one O(5)SrU3 trigonal pyramid, and  an edgeedge with one O(6)SrU3 trigonal pyramid. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Sr(3), one U(1), one U(2), and one U(3) atom. In the third O site, O(3) is bonded to one Sr(3), two equivalent Sr(2), and one U(3) atom to form OSr3U tetrahedra that share  a cornercorner with one O(3)Sr3U tetrahedra, corners with two equivalent O(1)Sr3U tetrahedra, corners with two equivalent O(7)Sr3U tetrahedra, corners with two equivalent O(8)Sr3U tetrahedra, corners with three equivalent O(4)Sr3U tetrahedra,  a cornercorner with one O(5)SrU3 trigonal pyramid,  a cornercorner with one O(6)SrU3 trigonal pyramid, corners with two equivalent O(9)SrU3 trigonal pyramids,  an edgeedge with one O(3)Sr3U tetrahedra,  an edgeedge with one O(7)Sr3U tetrahedra,  an edgeedge with one O(8)Sr3U tetrahedra,  an edgeedge with one O(6)SrU3 trigonal pyramid, and  an edgeedge with one O(9)SrU3 trigonal pyramid. In the fourth O site, O(4) is bonded to one Sr(2), two equivalent Sr(1), and one U(3) atom to form distorted OSr3U tetrahedra that share  a cornercorner with one O(7)Sr3U tetrahedra, corners with three equivalent O(1)Sr3U tetrahedra, corners with three equivalent O(3)Sr3U tetrahedra, corners with three equivalent O(8)Sr3U tetrahedra,  a cornercorner with one O(5)SrU3 trigonal pyramid,  a cornercorner with one O(9)SrU3 trigonal pyramid, corners with two equivalent O(6)SrU3 trigonal pyramids,  an edgeedge with one O(1)Sr3U tetrahedra,  an edgeedge with one O(4)Sr3U tetrahedra,  an edgeedge with one O(7)Sr3U tetrahedra,  an edgeedge with one O(5)SrU3 trigonal pyramid, and  an edgeedge with one O(9)SrU3 trigonal pyramid. In the fifth O site, O(5) is bonded to one Sr(1), one U(3), and two equivalent U(2) atoms to form distorted OSrU3 trigonal pyramids that share  a cornercorner with one O(3)Sr3U tetrahedra,  a cornercorner with one O(4)Sr3U tetrahedra,  a cornercorner with one O(7)Sr3U tetrahedra,  a cornercorner with one O(8)Sr3U tetrahedra, corners with two equivalent O(1)Sr3U tetrahedra, corners with two equivalent O(9)SrU3 trigonal pyramids, corners with three equivalent O(6)SrU3 trigonal pyramids,  an edgeedge with one O(1)Sr3U tetrahedra,  an edgeedge with one O(4)Sr3U tetrahedra,  an edgeedge with one O(7)Sr3U tetrahedra,  an edgeedge with one O(5)SrU3 trigonal pyramid, and  an edgeedge with one O(6)SrU3 trigonal pyramid. In the sixth O site, O(6) is bonded to one Sr(2), one U(3), and two equivalent U(2) atoms to form distorted OSrU3 trigonal pyramids that share  a cornercorner with one O(1)Sr3U tetrahedra,  a cornercorner with one O(3)Sr3U tetrahedra,  a cornercorner with one O(7)Sr3U tetrahedra,  a cornercorner with one O(8)Sr3U tetrahedra, corners with two equivalent O(4)Sr3U tetrahedra, corners with three equivalent O(5)SrU3 trigonal pyramids, corners with three equivalent O(9)SrU3 trigonal pyramids,  an edgeedge with one O(1)Sr3U tetrahedra,  an edgeedge with one O(3)Sr3U tetrahedra,  an edgeedge with one O(7)Sr3U tetrahedra,  an edgeedge with one O(5)SrU3 trigonal pyramid, and  an edgeedge with one O(6)SrU3 trigonal pyramid. In the seventh O site, O(7) is bonded to one Sr(1), one Sr(2), one Sr(3), and one U(2) atom to form OSr3U tetrahedra that share  a cornercorner with one O(4)Sr3U tetrahedra,  a cornercorner with one O(7)Sr3U tetrahedra, corners with two equivalent O(3)Sr3U tetrahedra, corners with two equivalent O(8)Sr3U tetrahedra, corners with four equivalent O(1)Sr3U tetrahedra,  a cornercorner with one O(5)SrU3 trigonal pyramid,  a cornercorner with one O(6)SrU3 trigonal pyramid,  a cornercorner with one O(9)SrU3 trigonal pyramid,  an edgeedge with one O(3)Sr3U tetrahedra,  an edgeedge with one O(4)Sr3U tetrahedra,  an edgeedge with one O(8)Sr3U tetrahedra,  an edgeedge with one O(5)SrU3 trigonal pyramid, and  an edgeedge with one O(6)SrU3 trigonal pyramid. In the eighth O site, O(8) is bonded to one Sr(1), one Sr(2), one Sr(3), and one U(1) atom to form distorted OSr3U tetrahedra that share  a cornercorner with one O(1)Sr3U tetrahedra, corners with two equivalent O(3)Sr3U tetrahedra, corners with two equivalent O(7)Sr3U tetrahedra, corners with two equivalent O(8)Sr3U tetrahedra, corners with three equivalent O(4)Sr3U tetrahedra,  a cornercorner with one O(5)SrU3 trigonal pyramid,  a cornercorner with one O(6)SrU3 trigonal pyramid,  a cornercorner with one O(9)SrU3 trigonal pyramid,  an edgeedge with one O(1)Sr3U tetrahedra,  an edgeedge with one O(3)Sr3U tetrahedra,  an edgeedge with one O(7)Sr3U tetrahedra, and  an edgeedge with one O(9)SrU3 trigonal pyramid. In the ninth O site, O(9) is bonded to one Sr(2), one U(1), and two equivalent U(3) atoms to form distorted OSrU3 trigonal pyramids that share  a cornercorner with one O(1)Sr3U tetrahedra,  a cornercorner with one O(4)Sr3U tetrahedra,  a cornercorner with one O(7)Sr3U tetrahedra,  a cornercorner with one O(8)Sr3U tetrahedra, corners with two equivalent O(3)Sr3U tetrahedra,  a cornercorner with one O(9)SrU3 trigonal pyramid, corners with two equivalent O(5)SrU3 trigonal pyramids, corners with three equivalent O(6)SrU3 trigonal pyramids,  an edgeedge with one O(3)Sr3U tetrahedra,  an edgeedge with one O(4)Sr3U tetrahedra,  an edgeedge with one O(8)Sr3U tetrahedra, and  an edgeedge with one O(9)SrU3 trigonal pyramid. is represented by the CIF card [CIF]
data_Sr5U5O18
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.950
_cell_length_b   7.739
_cell_length_c   8.724
_cell_angle_alpha   100.611
_cell_angle_beta   97.996
_cell_angle_gamma   107.390
_symmetry_Int_Tables_number   1
_cell_volume   430.637
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Sr  Sr0  1  0.800  0.103  0.581  1.0
  Sr  Sr1  1  0.593  0.695  0.195  1.0
  Sr  Sr2  1  0.407  0.305  0.805  1.0
  Sr  Sr3  1  0.200  0.897  0.419  1.0
  Sr  Sr4  1  0.000  0.500  0.000  1.0
  U  U5  1  0.000  0.000  0.000  1.0
  U  U6  1  0.791  0.580  0.587  1.0
  U  U7  1  0.621  0.200  0.196  1.0
  U  U8  1  0.379  0.800  0.804  1.0
  U  U9  1  0.209  0.420  0.413  1.0
  O  O10  1  0.827  0.784  0.468  1.0
  O  O11  1  0.013  0.228  0.176  1.0
  O  O12  1  0.666  0.399  0.071  1.0
  O  O13  1  0.456  0.998  0.684  1.0
  O  O14  1  0.861  0.351  0.412  1.0
  O  O15  1  0.496  0.390  0.349  1.0
  O  O16  1  0.244  0.607  0.280  1.0
  O  O17  1  0.980  0.830  0.146  1.0
  O  O18  1  0.668  0.944  0.992  1.0
  O  O19  1  0.332  0.056  0.008  1.0
  O  O20  1  0.020  0.170  0.854  1.0
  O  O21  1  0.756  0.393  0.720  1.0
  O  O22  1  0.504  0.610  0.651  1.0
  O  O23  1  0.139  0.649  0.588  1.0
  O  O24  1  0.544  0.002  0.316  1.0
  O  O25  1  0.334  0.601  0.929  1.0
  O  O26  1  0.987  0.772  0.824  1.0
  O  O27  1  0.173  0.216  0.532  1.0
[/CIF]
.
The compound described by Sr5U5O18 crystallizes in the triclinic P-1 space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one O(5), one O(7), one O(8), two equivalent O(1), and two equivalent O(4) atoms to form distorted SrO7 pentagonal bipyramids that share  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one U(2)O7 pentagonal bipyramid, edges with two equivalent Sr(1)O7 pentagonal bipyramids, and edges with two equivalent U(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 53°. In the second Sr site, Sr(2) is bonded in a distorted body-centered cubic geometry to one O(1), one O(4), one O(6), one O(7), one O(8), one O(9), and two equivalent O(3) atoms. In the third Sr site, Sr(3) is bonded in a distorted body-centered cubic geometry to two equivalent O(2), two equivalent O(3), two equivalent O(7), and two equivalent O(8) atoms. There are three inequivalent U sites. In the first U site, U(1) is bonded to two equivalent O(2), two equivalent O(8), and two equivalent O(9) atoms to form UO6 octahedra that share corners with two equivalent Sr(1)O7 pentagonal bipyramids and corners with two equivalent U(2)O7 pentagonal bipyramids. In the second U site, U(2) is bonded to one O(1), one O(2), one O(7), two equivalent O(5), and two equivalent O(6) atoms to form distorted UO7 pentagonal bipyramids that share  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one Sr(1)O7 pentagonal bipyramid, edges with two equivalent Sr(1)O7 pentagonal bipyramids, and edges with two equivalent U(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 38°. In the third U site, U(3) is bonded in a 7-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(9) atoms. There are nine inequivalent O sites. In the first O site, O(1) is bonded to one Sr(2), two equivalent Sr(1), and one U(2) atom to form distorted OSr3U tetrahedra that share  a cornercorner with one O(8)Sr3U tetrahedra, corners with two equivalent O(3)Sr3U tetrahedra, corners with three equivalent O(4)Sr3U tetrahedra, corners with four equivalent O(7)Sr3U tetrahedra,  a cornercorner with one O(6)SrU3 trigonal pyramid,  a cornercorner with one O(9)SrU3 trigonal pyramid, corners with two equivalent O(5)SrU3 trigonal pyramids,  an edgeedge with one O(1)Sr3U tetrahedra,  an edgeedge with one O(4)Sr3U tetrahedra,  an edgeedge with one O(8)Sr3U tetrahedra,  an edgeedge with one O(5)SrU3 trigonal pyramid, and  an edgeedge with one O(6)SrU3 trigonal pyramid. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Sr(3), one U(1), one U(2), and one U(3) atom. In the third O site, O(3) is bonded to one Sr(3), two equivalent Sr(2), and one U(3) atom to form OSr3U tetrahedra that share  a cornercorner with one O(3)Sr3U tetrahedra, corners with two equivalent O(1)Sr3U tetrahedra, corners with two equivalent O(7)Sr3U tetrahedra, corners with two equivalent O(8)Sr3U tetrahedra, corners with three equivalent O(4)Sr3U tetrahedra,  a cornercorner with one O(5)SrU3 trigonal pyramid,  a cornercorner with one O(6)SrU3 trigonal pyramid, corners with two equivalent O(9)SrU3 trigonal pyramids,  an edgeedge with one O(3)Sr3U tetrahedra,  an edgeedge with one O(7)Sr3U tetrahedra,  an edgeedge with one O(8)Sr3U tetrahedra,  an edgeedge with one O(6)SrU3 trigonal pyramid, and  an edgeedge with one O(9)SrU3 trigonal pyramid. In the fourth O site, O(4) is bonded to one Sr(2), two equivalent Sr(1), and one U(3) atom to form distorted OSr3U tetrahedra that share  a cornercorner with one O(7)Sr3U tetrahedra, corners with three equivalent O(1)Sr3U tetrahedra, corners with three equivalent O(3)Sr3U tetrahedra, corners with three equivalent O(8)Sr3U tetrahedra,  a cornercorner with one O(5)SrU3 trigonal pyramid,  a cornercorner with one O(9)SrU3 trigonal pyramid, corners with two equivalent O(6)SrU3 trigonal pyramids,  an edgeedge with one O(1)Sr3U tetrahedra,  an edgeedge with one O(4)Sr3U tetrahedra,  an edgeedge with one O(7)Sr3U tetrahedra,  an edgeedge with one O(5)SrU3 trigonal pyramid, and  an edgeedge with one O(9)SrU3 trigonal pyramid. In the fifth O site, O(5) is bonded to one Sr(1), one U(3), and two equivalent U(2) atoms to form distorted OSrU3 trigonal pyramids that share  a cornercorner with one O(3)Sr3U tetrahedra,  a cornercorner with one O(4)Sr3U tetrahedra,  a cornercorner with one O(7)Sr3U tetrahedra,  a cornercorner with one O(8)Sr3U tetrahedra, corners with two equivalent O(1)Sr3U tetrahedra, corners with two equivalent O(9)SrU3 trigonal pyramids, corners with three equivalent O(6)SrU3 trigonal pyramids,  an edgeedge with one O(1)Sr3U tetrahedra,  an edgeedge with one O(4)Sr3U tetrahedra,  an edgeedge with one O(7)Sr3U tetrahedra,  an edgeedge with one O(5)SrU3 trigonal pyramid, and  an edgeedge with one O(6)SrU3 trigonal pyramid. In the sixth O site, O(6) is bonded to one Sr(2), one U(3), and two equivalent U(2) atoms to form distorted OSrU3 trigonal pyramids that share  a cornercorner with one O(1)Sr3U tetrahedra,  a cornercorner with one O(3)Sr3U tetrahedra,  a cornercorner with one O(7)Sr3U tetrahedra,  a cornercorner with one O(8)Sr3U tetrahedra, corners with two equivalent O(4)Sr3U tetrahedra, corners with three equivalent O(5)SrU3 trigonal pyramids, corners with three equivalent O(9)SrU3 trigonal pyramids,  an edgeedge with one O(1)Sr3U tetrahedra,  an edgeedge with one O(3)Sr3U tetrahedra,  an edgeedge with one O(7)Sr3U tetrahedra,  an edgeedge with one O(5)SrU3 trigonal pyramid, and  an edgeedge with one O(6)SrU3 trigonal pyramid. In the seventh O site, O(7) is bonded to one Sr(1), one Sr(2), one Sr(3), and one U(2) atom to form OSr3U tetrahedra that share  a cornercorner with one O(4)Sr3U tetrahedra,  a cornercorner with one O(7)Sr3U tetrahedra, corners with two equivalent O(3)Sr3U tetrahedra, corners with two equivalent O(8)Sr3U tetrahedra, corners with four equivalent O(1)Sr3U tetrahedra,  a cornercorner with one O(5)SrU3 trigonal pyramid,  a cornercorner with one O(6)SrU3 trigonal pyramid,  a cornercorner with one O(9)SrU3 trigonal pyramid,  an edgeedge with one O(3)Sr3U tetrahedra,  an edgeedge with one O(4)Sr3U tetrahedra,  an edgeedge with one O(8)Sr3U tetrahedra,  an edgeedge with one O(5)SrU3 trigonal pyramid, and  an edgeedge with one O(6)SrU3 trigonal pyramid. In the eighth O site, O(8) is bonded to one Sr(1), one Sr(2), one Sr(3), and one U(1) atom to form distorted OSr3U tetrahedra that share  a cornercorner with one O(1)Sr3U tetrahedra, corners with two equivalent O(3)Sr3U tetrahedra, corners with two equivalent O(7)Sr3U tetrahedra, corners with two equivalent O(8)Sr3U tetrahedra, corners with three equivalent O(4)Sr3U tetrahedra,  a cornercorner with one O(5)SrU3 trigonal pyramid,  a cornercorner with one O(6)SrU3 trigonal pyramid,  a cornercorner with one O(9)SrU3 trigonal pyramid,  an edgeedge with one O(1)Sr3U tetrahedra,  an edgeedge with one O(3)Sr3U tetrahedra,  an edgeedge with one O(7)Sr3U tetrahedra, and  an edgeedge with one O(9)SrU3 trigonal pyramid. In the ninth O site, O(9) is bonded to one Sr(2), one U(1), and two equivalent U(3) atoms to form distorted OSrU3 trigonal pyramids that share  a cornercorner with one O(1)Sr3U tetrahedra,  a cornercorner with one O(4)Sr3U tetrahedra,  a cornercorner with one O(7)Sr3U tetrahedra,  a cornercorner with one O(8)Sr3U tetrahedra, corners with two equivalent O(3)Sr3U tetrahedra,  a cornercorner with one O(9)SrU3 trigonal pyramid, corners with two equivalent O(5)SrU3 trigonal pyramids, corners with three equivalent O(6)SrU3 trigonal pyramids,  an edgeedge with one O(3)Sr3U tetrahedra,  an edgeedge with one O(4)Sr3U tetrahedra,  an edgeedge with one O(8)Sr3U tetrahedra, and  an edgeedge with one O(9)SrU3 trigonal pyramid. is represented by the CIF card [CIF]
data_Sr5U5O18
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.950
_cell_length_b   7.739
_cell_length_c   8.724
_cell_angle_alpha   100.611
_cell_angle_beta   97.996
_cell_angle_gamma   107.390
_symmetry_Int_Tables_number   1
_cell_volume   430.637
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Sr  Sr0  1  0.800  0.103  0.581  1.0
  Sr  Sr1  1  0.593  0.695  0.195  1.0
  Sr  Sr2  1  0.407  0.305  0.805  1.0
  Sr  Sr3  1  0.200  0.897  0.419  1.0
  Sr  Sr4  1  0.000  0.500  0.000  1.0
  U  U5  1  0.000  0.000  0.000  1.0
  U  U6  1  0.791  0.580  0.587  1.0
  U  U7  1  0.621  0.200  0.196  1.0
  U  U8  1  0.379  0.800  0.804  1.0
  U  U9  1  0.209  0.420  0.413  1.0
  O  O10  1  0.827  0.784  0.468  1.0
  O  O11  1  0.013  0.228  0.176  1.0
  O  O12  1  0.666  0.399  0.071  1.0
  O  O13  1  0.456  0.998  0.684  1.0
  O  O14  1  0.861  0.351  0.412  1.0
  O  O15  1  0.496  0.390  0.349  1.0
  O  O16  1  0.244  0.607  0.280  1.0
  O  O17  1  0.980  0.830  0.146  1.0
  O  O18  1  0.668  0.944  0.992  1.0
  O  O19  1  0.332  0.056  0.008  1.0
  O  O20  1  0.020  0.170  0.854  1.0
  O  O21  1  0.756  0.393  0.720  1.0
  O  O22  1  0.504  0.610  0.651  1.0
  O  O23  1  0.139  0.649  0.588  1.0
  O  O24  1  0.544  0.002  0.316  1.0
  O  O25  1  0.334  0.601  0.929  1.0
  O  O26  1  0.987  0.772  0.824  1.0
  O  O27  1  0.173  0.216  0.532  1.0
[/CIF]
.