The compound described by U3O8 crystallizes in the orthorhombic Amm2 space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to one O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted UO7 pentagonal bipyramids that share corners with four equivalent U(2)O6 octahedra, corners with two equivalent U(1)O7 pentagonal bipyramids, and edges with two equivalent U(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-58°. In the second U site, U(2) is bonded to one O(1), one O(3), two equivalent O(4), and two equivalent O(5) atoms to form distorted UO6 octahedra that share corners with five equivalent U(2)O6 octahedra, corners with two equivalent U(1)O7 pentagonal bipyramids, and  an edgeedge with one U(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 3-59°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one U(1) and two equivalent U(2) atoms. In the second O site, O(2) is bonded in a linear geometry to two equivalent U(1) atoms. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one U(1) and one U(2) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one U(1) and two equivalent U(2) atoms. In the fifth O site, O(5) is bonded in a linear geometry to two equivalent U(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_U3O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.160
_cell_length_b   6.777
_cell_length_c   6.873
_cell_angle_alpha   119.541
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   168.591
_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
  U  U0  1  0.000  0.962  0.000  1.0
  U  U1  1  0.000  0.668  0.347  1.0
  U  U2  1  0.000  0.321  0.653  1.0
  O  O3  1  0.000  0.581  0.000  1.0
  O  O4  1  0.500  0.954  0.000  1.0
  O  O5  1  0.000  0.073  0.755  1.0
  O  O6  1  0.000  0.318  0.245  1.0
  O  O7  1  0.000  0.988  0.338  1.0
  O  O8  1  0.000  0.650  0.662  1.0
  O  O9  1  0.500  0.675  0.355  1.0
  O  O10  1  0.500  0.320  0.645  1.0
[/CIF]
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The compound described by U3O8 crystallizes in the orthorhombic Amm2 space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to one O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted UO7 pentagonal bipyramids that share corners with four equivalent U(2)O6 octahedra, corners with two equivalent U(1)O7 pentagonal bipyramids, and edges with two equivalent U(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-58°. In the second U site, U(2) is bonded to one O(1), one O(3), two equivalent O(4), and two equivalent O(5) atoms to form distorted UO6 octahedra that share corners with five equivalent U(2)O6 octahedra, corners with two equivalent U(1)O7 pentagonal bipyramids, and  an edgeedge with one U(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 3-59°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one U(1) and two equivalent U(2) atoms. In the second O site, O(2) is bonded in a linear geometry to two equivalent U(1) atoms. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one U(1) and one U(2) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one U(1) and two equivalent U(2) atoms. In the fifth O site, O(5) is bonded in a linear geometry to two equivalent U(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_U3O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.160
_cell_length_b   6.777
_cell_length_c   6.873
_cell_angle_alpha   119.541
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   168.591
_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
  U  U0  1  0.000  0.962  0.000  1.0
  U  U1  1  0.000  0.668  0.347  1.0
  U  U2  1  0.000  0.321  0.653  1.0
  O  O3  1  0.000  0.581  0.000  1.0
  O  O4  1  0.500  0.954  0.000  1.0
  O  O5  1  0.000  0.073  0.755  1.0
  O  O6  1  0.000  0.318  0.245  1.0
  O  O7  1  0.000  0.988  0.338  1.0
  O  O8  1  0.000  0.650  0.662  1.0
  O  O9  1  0.500  0.675  0.355  1.0
  O  O10  1  0.500  0.320  0.645  1.0
[/CIF]
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