The material described by U2La2Se9 crystallizes in the orthorhombic Pmma space group. U(1) is bonded in a 9-coordinate geometry to one Se(1), two equivalent Se(2), two equivalent Se(3), two equivalent Se(4), and two equivalent Se(5) atoms. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 10-coordinate geometry to two equivalent Se(1), two equivalent Se(2), two equivalent Se(5), and four equivalent Se(4) atoms. In the second La site, La(2) is bonded in a 10-coordinate geometry to two equivalent Se(5), four equivalent Se(2), and four equivalent Se(3) atoms. There are five inequivalent Se sites. In the first Se site, Se(1) is bonded in a see-saw-like geometry to two equivalent U(1) and two equivalent La(1) atoms. In the second Se site, Se(2) is bonded to two equivalent U(1), one La(1), and two equivalent La(2) atoms to form a mixture of distorted corner and edge-sharing SeLa3U2 trigonal bipyramids. In the third Se site, Se(3) is bonded in a 6-coordinate geometry to two equivalent U(1), two equivalent La(2), and two equivalent Se(3) atoms. In the fourth Se site, Se(4) is bonded in a 6-coordinate geometry to two equivalent U(1), two equivalent La(1), and two equivalent Se(4) atoms. In the fifth Se site, Se(5) is bonded in a 6-coordinate geometry to two equivalent U(1), one La(1), one La(2), and two equivalent Se(5) atoms. is represented by the CIF file [CIF]
data_La2U2Se9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.643
_cell_length_b   10.695
_cell_length_c   10.750
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   648.794
_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
  La  La0  1  0.500  0.575  0.250  1.0
  La  La1  1  0.500  0.425  0.750  1.0
  La  La2  1  0.500  0.026  0.250  1.0
  La  La3  1  0.500  0.974  0.750  1.0
  U  U4  1  0.000  0.256  0.490  1.0
  U  U5  1  0.000  0.744  0.510  1.0
  U  U6  1  0.000  0.256  0.010  1.0
  U  U7  1  0.000  0.744  0.990  1.0
  Se  Se8  1  0.000  0.684  0.250  1.0
  Se  Se9  1  0.000  0.316  0.750  1.0
  Se  Se10  1  0.500  0.188  0.945  1.0
  Se  Se11  1  0.500  0.812  0.055  1.0
  Se  Se12  1  0.500  0.188  0.555  1.0
  Se  Se13  1  0.500  0.812  0.445  1.0
  Se  Se14  1  0.000  0.000  0.378  1.0
  Se  Se15  1  0.000  1.000  0.622  1.0
  Se  Se16  1  0.000  0.000  0.122  1.0
  Se  Se17  1  0.000  1.000  0.878  1.0
  Se  Se18  1  0.750  0.500  0.500  1.0
  Se  Se19  1  0.750  0.500  0.000  1.0
  Se  Se20  1  0.250  0.500  0.500  1.0
  Se  Se21  1  0.250  0.500  0.000  1.0
  Se  Se22  1  0.749  0.286  0.250  1.0
  Se  Se23  1  0.749  0.714  0.750  1.0
  Se  Se24  1  0.251  0.714  0.750  1.0
  Se  Se25  1  0.251  0.286  0.250  1.0
[/CIF]
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The material described by U2La2Se9 crystallizes in the orthorhombic Pmma space group. U(1) is bonded in a 9-coordinate geometry to one Se(1), two equivalent Se(2), two equivalent Se(3), two equivalent Se(4), and two equivalent Se(5) atoms. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 10-coordinate geometry to two equivalent Se(1), two equivalent Se(2), two equivalent Se(5), and four equivalent Se(4) atoms. In the second La site, La(2) is bonded in a 10-coordinate geometry to two equivalent Se(5), four equivalent Se(2), and four equivalent Se(3) atoms. There are five inequivalent Se sites. In the first Se site, Se(1) is bonded in a see-saw-like geometry to two equivalent U(1) and two equivalent La(1) atoms. In the second Se site, Se(2) is bonded to two equivalent U(1), one La(1), and two equivalent La(2) atoms to form a mixture of distorted corner and edge-sharing SeLa3U2 trigonal bipyramids. In the third Se site, Se(3) is bonded in a 6-coordinate geometry to two equivalent U(1), two equivalent La(2), and two equivalent Se(3) atoms. In the fourth Se site, Se(4) is bonded in a 6-coordinate geometry to two equivalent U(1), two equivalent La(1), and two equivalent Se(4) atoms. In the fifth Se site, Se(5) is bonded in a 6-coordinate geometry to two equivalent U(1), one La(1), one La(2), and two equivalent Se(5) atoms. is represented by the CIF file [CIF]
data_La2U2Se9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.643
_cell_length_b   10.695
_cell_length_c   10.750
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   648.794
_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
  La  La0  1  0.500  0.575  0.250  1.0
  La  La1  1  0.500  0.425  0.750  1.0
  La  La2  1  0.500  0.026  0.250  1.0
  La  La3  1  0.500  0.974  0.750  1.0
  U  U4  1  0.000  0.256  0.490  1.0
  U  U5  1  0.000  0.744  0.510  1.0
  U  U6  1  0.000  0.256  0.010  1.0
  U  U7  1  0.000  0.744  0.990  1.0
  Se  Se8  1  0.000  0.684  0.250  1.0
  Se  Se9  1  0.000  0.316  0.750  1.0
  Se  Se10  1  0.500  0.188  0.945  1.0
  Se  Se11  1  0.500  0.812  0.055  1.0
  Se  Se12  1  0.500  0.188  0.555  1.0
  Se  Se13  1  0.500  0.812  0.445  1.0
  Se  Se14  1  0.000  0.000  0.378  1.0
  Se  Se15  1  0.000  1.000  0.622  1.0
  Se  Se16  1  0.000  0.000  0.122  1.0
  Se  Se17  1  0.000  1.000  0.878  1.0
  Se  Se18  1  0.750  0.500  0.500  1.0
  Se  Se19  1  0.750  0.500  0.000  1.0
  Se  Se20  1  0.250  0.500  0.500  1.0
  Se  Se21  1  0.250  0.500  0.000  1.0
  Se  Se22  1  0.749  0.286  0.250  1.0
  Se  Se23  1  0.749  0.714  0.750  1.0
  Se  Se24  1  0.251  0.714  0.750  1.0
  Se  Se25  1  0.251  0.286  0.250  1.0
[/CIF]
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