The crystal structure described by Eu(AlSe2)2 crystallizes in the orthorhombic Cccm space group. Eu(1) is bonded in a 8-coordinate geometry to four equivalent Se(1) and four equivalent Se(2) atoms. Al(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form edge-sharing AlSe4 tetrahedra. There are two inequivalent Se sites. In the first Se site, Se(2) is bonded in a 4-coordinate geometry to two equivalent Eu(1) and two equivalent Al(1) atoms. In the second Se site, Se(1) is bonded to two equivalent Eu(1) and two equivalent Al(1) atoms to form a mixture of distorted edge and corner-sharing SeEu2Al2 trigonal pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Eu(AlSe2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.279
_cell_length_b   6.279
_cell_length_c   10.941
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.588
_symmetry_Int_Tables_number   1
_cell_volume   371.317
_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
  Eu  Eu0  1  0.500  0.500  0.250  1.0
  Eu  Eu1  1  0.500  0.500  0.750  1.0
  Al  Al2  1  0.758  0.240  0.500  1.0
  Al  Al3  1  0.242  0.760  0.500  1.0
  Al  Al4  1  0.760  0.242  0.000  1.0
  Al  Al5  1  0.240  0.758  0.000  1.0
  Se  Se6  1  0.818  0.651  0.500  1.0
  Se  Se7  1  0.182  0.349  0.500  1.0
  Se  Se8  1  0.349  0.182  0.000  1.0
  Se  Se9  1  0.651  0.818  0.000  1.0
  Se  Se10  1  0.000  0.500  0.167  1.0
  Se  Se11  1  0.500  0.000  0.333  1.0
  Se  Se12  1  0.000  0.500  0.833  1.0
  Se  Se13  1  0.500  0.000  0.667  1.0
[/CIF]
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The crystal structure described by Eu(AlSe2)2 crystallizes in the orthorhombic Cccm space group. Eu(1) is bonded in a 8-coordinate geometry to four equivalent Se(1) and four equivalent Se(2) atoms. Al(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form edge-sharing AlSe4 tetrahedra. There are two inequivalent Se sites. In the first Se site, Se(2) is bonded in a 4-coordinate geometry to two equivalent Eu(1) and two equivalent Al(1) atoms. In the second Se site, Se(1) is bonded to two equivalent Eu(1) and two equivalent Al(1) atoms to form a mixture of distorted edge and corner-sharing SeEu2Al2 trigonal pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Eu(AlSe2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.279
_cell_length_b   6.279
_cell_length_c   10.941
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.588
_symmetry_Int_Tables_number   1
_cell_volume   371.317
_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
  Eu  Eu0  1  0.500  0.500  0.250  1.0
  Eu  Eu1  1  0.500  0.500  0.750  1.0
  Al  Al2  1  0.758  0.240  0.500  1.0
  Al  Al3  1  0.242  0.760  0.500  1.0
  Al  Al4  1  0.760  0.242  0.000  1.0
  Al  Al5  1  0.240  0.758  0.000  1.0
  Se  Se6  1  0.818  0.651  0.500  1.0
  Se  Se7  1  0.182  0.349  0.500  1.0
  Se  Se8  1  0.349  0.182  0.000  1.0
  Se  Se9  1  0.651  0.818  0.000  1.0
  Se  Se10  1  0.000  0.500  0.167  1.0
  Se  Se11  1  0.500  0.000  0.333  1.0
  Se  Se12  1  0.000  0.500  0.833  1.0
  Se  Se13  1  0.500  0.000  0.667  1.0
[/CIF]
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