The crystal structure described by K2U2O7 crystallizes in the monoclinic Pm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form KO6 octahedra that share corners with four equivalent U(2)O6 octahedra, edges with two equivalent K(1)O6 octahedra, and edges with four equivalent K(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-58°. In the second K site, K(2) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form distorted KO6 octahedra that share corners with two equivalent U(2)O6 octahedra, edges with two equivalent K(2)O6 octahedra, and edges with four equivalent K(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 59-60°. There are two inequivalent U sites. In the first U site, U(1) is bonded in a 7-coordinate geometry to one O(2), one O(4), one O(6), two equivalent O(5), and two equivalent O(7) atoms. In the second U site, U(2) is bonded to one O(1), one O(3), one O(5), one O(7), and two equivalent O(6) atoms to form distorted UO6 octahedra that share corners with two equivalent K(2)O6 octahedra, corners with two equivalent U(2)O6 octahedra, and corners with four equivalent K(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-60°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one K(2), two equivalent K(1), and one U(2) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one K(1), two equivalent K(2), and one U(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one K(2), two equivalent K(1), and one U(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one K(1), two equivalent K(2), and one U(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one U(2) and two equivalent U(1) atoms. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one U(1) and two equivalent U(2) atoms. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one U(2) and two equivalent U(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_K2U2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.035
_cell_length_b   6.988
_cell_length_c   7.183
_cell_angle_alpha   71.121
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   191.622
_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
  K  K0  1  0.000  0.501  0.505  1.0
  K  K1  1  0.500  0.001  0.499  1.0
  U  U2  1  0.000  0.981  0.003  1.0
  U  U3  1  0.500  0.512  0.011  1.0
  O  O4  1  0.500  0.590  0.731  1.0
  O  O5  1  0.000  0.093  0.728  1.0
  O  O6  1  0.500  0.417  0.292  1.0
  O  O7  1  0.000  0.895  0.278  1.0
  O  O8  1  0.500  0.848  0.980  1.0
  O  O9  1  0.000  0.612  0.022  1.0
  O  O10  1  0.500  0.194  0.023  1.0
[/CIF]
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The crystal structure described by K2U2O7 crystallizes in the monoclinic Pm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form KO6 octahedra that share corners with four equivalent U(2)O6 octahedra, edges with two equivalent K(1)O6 octahedra, and edges with four equivalent K(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-58°. In the second K site, K(2) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form distorted KO6 octahedra that share corners with two equivalent U(2)O6 octahedra, edges with two equivalent K(2)O6 octahedra, and edges with four equivalent K(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 59-60°. There are two inequivalent U sites. In the first U site, U(1) is bonded in a 7-coordinate geometry to one O(2), one O(4), one O(6), two equivalent O(5), and two equivalent O(7) atoms. In the second U site, U(2) is bonded to one O(1), one O(3), one O(5), one O(7), and two equivalent O(6) atoms to form distorted UO6 octahedra that share corners with two equivalent K(2)O6 octahedra, corners with two equivalent U(2)O6 octahedra, and corners with four equivalent K(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-60°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one K(2), two equivalent K(1), and one U(2) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one K(1), two equivalent K(2), and one U(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one K(2), two equivalent K(1), and one U(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one K(1), two equivalent K(2), and one U(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one U(2) and two equivalent U(1) atoms. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one U(1) and two equivalent U(2) atoms. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one U(2) and two equivalent U(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_K2U2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.035
_cell_length_b   6.988
_cell_length_c   7.183
_cell_angle_alpha   71.121
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   191.622
_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
  K  K0  1  0.000  0.501  0.505  1.0
  K  K1  1  0.500  0.001  0.499  1.0
  U  U2  1  0.000  0.981  0.003  1.0
  U  U3  1  0.500  0.512  0.011  1.0
  O  O4  1  0.500  0.590  0.731  1.0
  O  O5  1  0.000  0.093  0.728  1.0
  O  O6  1  0.500  0.417  0.292  1.0
  O  O7  1  0.000  0.895  0.278  1.0
  O  O8  1  0.500  0.848  0.980  1.0
  O  O9  1  0.000  0.612  0.022  1.0
  O  O10  1  0.500  0.194  0.023  1.0
[/CIF]
.