The crystal structure described by U2AsSe is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to three equivalent As(1) and three equivalent Se(1) atoms to form a mixture of corner and edge-sharing UAs3Se3 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the second U site, U(2) is bonded to three equivalent As(1) and three equivalent Se(1) atoms to form a mixture of corner and edge-sharing UAs3Se3 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. As(1) is bonded to three equivalent U(1) and three equivalent U(2) atoms to form AsU6 octahedra that share corners with two equivalent Se(1)U6 octahedra, corners with four equivalent As(1)U6 octahedra, edges with four equivalent As(1)U6 octahedra, and edges with eight equivalent Se(1)U6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. Se(1) is bonded to three equivalent U(1) and three equivalent U(2) atoms to form SeU6 octahedra that share corners with two equivalent As(1)U6 octahedra, corners with four equivalent Se(1)U6 octahedra, edges with four equivalent Se(1)U6 octahedra, and edges with eight equivalent As(1)U6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. is represented by the CIF file [CIF]
data_U2AsSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.078
_cell_length_b   7.078
_cell_length_c   5.775
_cell_angle_alpha   65.983
_cell_angle_beta   65.983
_cell_angle_gamma   48.195
_symmetry_Int_Tables_number   1
_cell_volume   193.060
_cell_formula_units_Z   2
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  0.874  0.874  0.880  1.0
  U  U1  1  0.376  0.376  0.370  1.0
  U  U2  1  0.126  0.126  0.120  1.0
  U  U3  1  0.624  0.624  0.630  1.0
  As  As4  1  0.625  0.625  0.130  1.0
  As  As5  1  0.375  0.375  0.870  1.0
  Se  Se6  1  0.125  0.125  0.627  1.0
  Se  Se7  1  0.875  0.875  0.373  1.0
[/CIF]
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The crystal structure described by U2AsSe is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to three equivalent As(1) and three equivalent Se(1) atoms to form a mixture of corner and edge-sharing UAs3Se3 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the second U site, U(2) is bonded to three equivalent As(1) and three equivalent Se(1) atoms to form a mixture of corner and edge-sharing UAs3Se3 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. As(1) is bonded to three equivalent U(1) and three equivalent U(2) atoms to form AsU6 octahedra that share corners with two equivalent Se(1)U6 octahedra, corners with four equivalent As(1)U6 octahedra, edges with four equivalent As(1)U6 octahedra, and edges with eight equivalent Se(1)U6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. Se(1) is bonded to three equivalent U(1) and three equivalent U(2) atoms to form SeU6 octahedra that share corners with two equivalent As(1)U6 octahedra, corners with four equivalent Se(1)U6 octahedra, edges with four equivalent Se(1)U6 octahedra, and edges with eight equivalent As(1)U6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. is represented by the CIF file [CIF]
data_U2AsSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.078
_cell_length_b   7.078
_cell_length_c   5.775
_cell_angle_alpha   65.983
_cell_angle_beta   65.983
_cell_angle_gamma   48.195
_symmetry_Int_Tables_number   1
_cell_volume   193.060
_cell_formula_units_Z   2
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  0.874  0.874  0.880  1.0
  U  U1  1  0.376  0.376  0.370  1.0
  U  U2  1  0.126  0.126  0.120  1.0
  U  U3  1  0.624  0.624  0.630  1.0
  As  As4  1  0.625  0.625  0.130  1.0
  As  As5  1  0.375  0.375  0.870  1.0
  Se  Se6  1  0.125  0.125  0.627  1.0
  Se  Se7  1  0.875  0.875  0.373  1.0
[/CIF]
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