The structure described by U2SmSe5 crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to one Se(3), one Se(4), one Se(5), two equivalent Se(1), and two equivalent Se(2) atoms to form distorted edge-sharing USe7 pentagonal bipyramids. In the second U site, U(2) is bonded in a 8-coordinate geometry to one Se(1), one Se(2), two equivalent Se(3), two equivalent Se(4), and two equivalent Se(5) atoms. Sm(1) is bonded in a 8-coordinate geometry to one Se(1), one Se(2), two equivalent Se(3), two equivalent Se(4), and two equivalent Se(5) atoms. There are five inequivalent Se sites. In the first Se site, Se(1) is bonded to one U(2), two equivalent U(1), and one Sm(1) atom to form distorted SeSmU3 trigonal pyramids that share corners with two equivalent Se(5)Sm2U3 square pyramids, corners with four equivalent Se(3)Sm2U3 square pyramids, corners with two equivalent Se(4)Sm2U3 trigonal bipyramids, corners with two equivalent Se(1)SmU3 trigonal pyramids, corners with four equivalent Se(2)SmU3 trigonal pyramids,  an edgeedge with one Se(3)Sm2U3 square pyramid, edges with two equivalent Se(5)Sm2U3 square pyramids, edges with two equivalent Se(4)Sm2U3 trigonal bipyramids, and  an edgeedge with one Se(2)SmU3 trigonal pyramid. In the second Se site, Se(2) is bonded to one U(2), two equivalent U(1), and one Sm(1) atom to form distorted SeSmU3 trigonal pyramids that share corners with two equivalent Se(5)Sm2U3 square pyramids, corners with four equivalent Se(3)Sm2U3 square pyramids, corners with two equivalent Se(4)Sm2U3 trigonal bipyramids, corners with two equivalent Se(2)SmU3 trigonal pyramids, corners with four equivalent Se(1)SmU3 trigonal pyramids,  an edgeedge with one Se(3)Sm2U3 square pyramid, edges with two equivalent Se(5)Sm2U3 square pyramids, edges with two equivalent Se(4)Sm2U3 trigonal bipyramids, and  an edgeedge with one Se(1)SmU3 trigonal pyramid. In the third Se site, Se(3) is bonded to one U(1), two equivalent U(2), and two equivalent Sm(1) atoms to form SeSm2U3 square pyramids that share corners with four equivalent Se(5)Sm2U3 square pyramids, corners with five equivalent Se(4)Sm2U3 trigonal bipyramids, corners with four equivalent Se(1)SmU3 trigonal pyramids, corners with four equivalent Se(2)SmU3 trigonal pyramids,  an edgeedge with one Se(5)Sm2U3 square pyramid, edges with two equivalent Se(3)Sm2U3 square pyramids, edges with two equivalent Se(4)Sm2U3 trigonal bipyramids,  an edgeedge with one Se(1)SmU3 trigonal pyramid,  an edgeedge with one Se(2)SmU3 trigonal pyramid, and  a faceface with one Se(5)Sm2U3 square pyramid. In the fourth Se site, Se(4) is bonded to one U(1), two equivalent U(2), and two equivalent Sm(1) atoms to form distorted SeSm2U3 trigonal bipyramids that share  a cornercorner with one Se(5)Sm2U3 square pyramid, corners with five equivalent Se(3)Sm2U3 square pyramids, corners with four equivalent Se(4)Sm2U3 trigonal bipyramids, corners with two equivalent Se(1)SmU3 trigonal pyramids, corners with two equivalent Se(2)SmU3 trigonal pyramids, edges with two equivalent Se(3)Sm2U3 square pyramids, edges with four equivalent Se(5)Sm2U3 square pyramids, edges with two equivalent Se(1)SmU3 trigonal pyramids, and edges with two equivalent Se(2)SmU3 trigonal pyramids. In the fifth Se site, Se(5) is bonded to one U(1), two equivalent U(2), and two equivalent Sm(1) atoms to form distorted SeSm2U3 square pyramids that share corners with four equivalent Se(3)Sm2U3 square pyramids, corners with four equivalent Se(5)Sm2U3 square pyramids,  a cornercorner with one Se(4)Sm2U3 trigonal bipyramid, corners with two equivalent Se(1)SmU3 trigonal pyramids, corners with two equivalent Se(2)SmU3 trigonal pyramids,  an edgeedge with one Se(3)Sm2U3 square pyramid, edges with four equivalent Se(4)Sm2U3 trigonal bipyramids, edges with two equivalent Se(1)SmU3 trigonal pyramids, edges with two equivalent Se(2)SmU3 trigonal pyramids, and  a faceface with one Se(3)Sm2U3 square pyramid. is represented by the Crystallographic Information File (CIF) [CIF]
data_SmU2Se5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.846
_cell_length_b   8.392
_cell_length_c   12.434
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   818.718
_cell_formula_units_Z   4
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
  Sm  Sm0  1  0.020  0.502  0.821  1.0
  Sm  Sm1  1  0.980  0.002  0.179  1.0
  Sm  Sm2  1  0.520  0.002  0.679  1.0
  Sm  Sm3  1  0.480  0.502  0.321  1.0
  U  U4  1  0.574  0.250  0.991  1.0
  U  U5  1  0.926  0.250  0.491  1.0
  U  U6  1  0.426  0.750  0.009  1.0
  U  U7  1  0.074  0.750  0.509  1.0
  U  U8  1  0.481  0.999  0.321  1.0
  U  U9  1  0.519  0.499  0.679  1.0
  U  U10  1  0.981  0.499  0.179  1.0
  U  U11  1  0.019  0.999  0.821  1.0
  Se  Se12  1  0.337  0.042  0.099  1.0
  Se  Se13  1  0.164  0.454  0.598  1.0
  Se  Se14  1  0.663  0.542  0.901  1.0
  Se  Se15  1  0.836  0.954  0.402  1.0
  Se  Se16  1  0.664  0.954  0.902  1.0
  Se  Se17  1  0.837  0.542  0.401  1.0
  Se  Se18  1  0.336  0.454  0.098  1.0
  Se  Se19  1  0.163  0.042  0.599  1.0
  Se  Se20  1  0.960  0.250  1.000  1.0
  Se  Se21  1  0.540  0.250  0.500  1.0
  Se  Se22  1  0.040  0.750  0.000  1.0
  Se  Se23  1  0.460  0.750  0.500  1.0
  Se  Se24  1  0.326  0.252  0.816  1.0
  Se  Se25  1  0.174  0.252  0.316  1.0
  Se  Se26  1  0.674  0.752  0.184  1.0
  Se  Se27  1  0.826  0.752  0.684  1.0
  Se  Se28  1  0.700  0.250  0.215  1.0
  Se  Se29  1  0.800  0.250  0.715  1.0
  Se  Se30  1  0.300  0.750  0.785  1.0
  Se  Se31  1  0.200  0.750  0.285  1.0
[/CIF]
.
The structure described by U2SmSe5 crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to one Se(3), one Se(4), one Se(5), two equivalent Se(1), and two equivalent Se(2) atoms to form distorted edge-sharing USe7 pentagonal bipyramids. In the second U site, U(2) is bonded in a 8-coordinate geometry to one Se(1), one Se(2), two equivalent Se(3), two equivalent Se(4), and two equivalent Se(5) atoms. Sm(1) is bonded in a 8-coordinate geometry to one Se(1), one Se(2), two equivalent Se(3), two equivalent Se(4), and two equivalent Se(5) atoms. There are five inequivalent Se sites. In the first Se site, Se(1) is bonded to one U(2), two equivalent U(1), and one Sm(1) atom to form distorted SeSmU3 trigonal pyramids that share corners with two equivalent Se(5)Sm2U3 square pyramids, corners with four equivalent Se(3)Sm2U3 square pyramids, corners with two equivalent Se(4)Sm2U3 trigonal bipyramids, corners with two equivalent Se(1)SmU3 trigonal pyramids, corners with four equivalent Se(2)SmU3 trigonal pyramids,  an edgeedge with one Se(3)Sm2U3 square pyramid, edges with two equivalent Se(5)Sm2U3 square pyramids, edges with two equivalent Se(4)Sm2U3 trigonal bipyramids, and  an edgeedge with one Se(2)SmU3 trigonal pyramid. In the second Se site, Se(2) is bonded to one U(2), two equivalent U(1), and one Sm(1) atom to form distorted SeSmU3 trigonal pyramids that share corners with two equivalent Se(5)Sm2U3 square pyramids, corners with four equivalent Se(3)Sm2U3 square pyramids, corners with two equivalent Se(4)Sm2U3 trigonal bipyramids, corners with two equivalent Se(2)SmU3 trigonal pyramids, corners with four equivalent Se(1)SmU3 trigonal pyramids,  an edgeedge with one Se(3)Sm2U3 square pyramid, edges with two equivalent Se(5)Sm2U3 square pyramids, edges with two equivalent Se(4)Sm2U3 trigonal bipyramids, and  an edgeedge with one Se(1)SmU3 trigonal pyramid. In the third Se site, Se(3) is bonded to one U(1), two equivalent U(2), and two equivalent Sm(1) atoms to form SeSm2U3 square pyramids that share corners with four equivalent Se(5)Sm2U3 square pyramids, corners with five equivalent Se(4)Sm2U3 trigonal bipyramids, corners with four equivalent Se(1)SmU3 trigonal pyramids, corners with four equivalent Se(2)SmU3 trigonal pyramids,  an edgeedge with one Se(5)Sm2U3 square pyramid, edges with two equivalent Se(3)Sm2U3 square pyramids, edges with two equivalent Se(4)Sm2U3 trigonal bipyramids,  an edgeedge with one Se(1)SmU3 trigonal pyramid,  an edgeedge with one Se(2)SmU3 trigonal pyramid, and  a faceface with one Se(5)Sm2U3 square pyramid. In the fourth Se site, Se(4) is bonded to one U(1), two equivalent U(2), and two equivalent Sm(1) atoms to form distorted SeSm2U3 trigonal bipyramids that share  a cornercorner with one Se(5)Sm2U3 square pyramid, corners with five equivalent Se(3)Sm2U3 square pyramids, corners with four equivalent Se(4)Sm2U3 trigonal bipyramids, corners with two equivalent Se(1)SmU3 trigonal pyramids, corners with two equivalent Se(2)SmU3 trigonal pyramids, edges with two equivalent Se(3)Sm2U3 square pyramids, edges with four equivalent Se(5)Sm2U3 square pyramids, edges with two equivalent Se(1)SmU3 trigonal pyramids, and edges with two equivalent Se(2)SmU3 trigonal pyramids. In the fifth Se site, Se(5) is bonded to one U(1), two equivalent U(2), and two equivalent Sm(1) atoms to form distorted SeSm2U3 square pyramids that share corners with four equivalent Se(3)Sm2U3 square pyramids, corners with four equivalent Se(5)Sm2U3 square pyramids,  a cornercorner with one Se(4)Sm2U3 trigonal bipyramid, corners with two equivalent Se(1)SmU3 trigonal pyramids, corners with two equivalent Se(2)SmU3 trigonal pyramids,  an edgeedge with one Se(3)Sm2U3 square pyramid, edges with four equivalent Se(4)Sm2U3 trigonal bipyramids, edges with two equivalent Se(1)SmU3 trigonal pyramids, edges with two equivalent Se(2)SmU3 trigonal pyramids, and  a faceface with one Se(3)Sm2U3 square pyramid. is represented by the Crystallographic Information File (CIF) [CIF]
data_SmU2Se5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.846
_cell_length_b   8.392
_cell_length_c   12.434
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   818.718
_cell_formula_units_Z   4
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
  Sm  Sm0  1  0.020  0.502  0.821  1.0
  Sm  Sm1  1  0.980  0.002  0.179  1.0
  Sm  Sm2  1  0.520  0.002  0.679  1.0
  Sm  Sm3  1  0.480  0.502  0.321  1.0
  U  U4  1  0.574  0.250  0.991  1.0
  U  U5  1  0.926  0.250  0.491  1.0
  U  U6  1  0.426  0.750  0.009  1.0
  U  U7  1  0.074  0.750  0.509  1.0
  U  U8  1  0.481  0.999  0.321  1.0
  U  U9  1  0.519  0.499  0.679  1.0
  U  U10  1  0.981  0.499  0.179  1.0
  U  U11  1  0.019  0.999  0.821  1.0
  Se  Se12  1  0.337  0.042  0.099  1.0
  Se  Se13  1  0.164  0.454  0.598  1.0
  Se  Se14  1  0.663  0.542  0.901  1.0
  Se  Se15  1  0.836  0.954  0.402  1.0
  Se  Se16  1  0.664  0.954  0.902  1.0
  Se  Se17  1  0.837  0.542  0.401  1.0
  Se  Se18  1  0.336  0.454  0.098  1.0
  Se  Se19  1  0.163  0.042  0.599  1.0
  Se  Se20  1  0.960  0.250  1.000  1.0
  Se  Se21  1  0.540  0.250  0.500  1.0
  Se  Se22  1  0.040  0.750  0.000  1.0
  Se  Se23  1  0.460  0.750  0.500  1.0
  Se  Se24  1  0.326  0.252  0.816  1.0
  Se  Se25  1  0.174  0.252  0.316  1.0
  Se  Se26  1  0.674  0.752  0.184  1.0
  Se  Se27  1  0.826  0.752  0.684  1.0
  Se  Se28  1  0.700  0.250  0.215  1.0
  Se  Se29  1  0.800  0.250  0.715  1.0
  Se  Se30  1  0.300  0.750  0.785  1.0
  Se  Se31  1  0.200  0.750  0.285  1.0
[/CIF]
.