The structure described by HgCr2Se4 is Spinel structured and crystallizes in the cubic Fd-3m space group. Cr(1) is bonded to six equivalent Se(1) atoms to form CrSe6 octahedra that share corners with six equivalent Hg(1)Se4 tetrahedra and edges with six equivalent Cr(1)Se6 octahedra. Hg(1) is bonded to four equivalent Se(1) atoms to form HgSe4 tetrahedra that share corners with twelve equivalent Cr(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 60°. Se(1) is bonded to three equivalent Cr(1) and one Hg(1) atom to form a mixture of distorted edge and corner-sharing SeCr3Hg tetrahedra. is represented by the CIF file [CIF]
data_Cr2HgSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.664
_cell_length_b   7.664
_cell_length_c   7.664
_cell_angle_alpha   60.000
_cell_angle_beta   60.000
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   318.290
_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
  Cr  Cr0  1  0.125  0.125  0.125  1.0
  Cr  Cr1  1  0.625  0.125  0.125  1.0
  Cr  Cr2  1  0.125  0.625  0.125  1.0
  Cr  Cr3  1  0.125  0.125  0.625  1.0
  Hg  Hg4  1  0.500  0.500  0.500  1.0
  Hg  Hg5  1  0.750  0.750  0.750  1.0
  Se  Se6  1  0.360  0.360  0.360  1.0
  Se  Se7  1  0.921  0.360  0.360  1.0
  Se  Se8  1  0.890  0.890  0.890  1.0
  Se  Se9  1  0.360  0.360  0.921  1.0
  Se  Se10  1  0.360  0.921  0.360  1.0
  Se  Se11  1  0.890  0.890  0.329  1.0
  Se  Se12  1  0.890  0.329  0.890  1.0
  Se  Se13  1  0.329  0.890  0.890  1.0
[/CIF]
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The structure described by HgCr2Se4 is Spinel structured and crystallizes in the cubic Fd-3m space group. Cr(1) is bonded to six equivalent Se(1) atoms to form CrSe6 octahedra that share corners with six equivalent Hg(1)Se4 tetrahedra and edges with six equivalent Cr(1)Se6 octahedra. Hg(1) is bonded to four equivalent Se(1) atoms to form HgSe4 tetrahedra that share corners with twelve equivalent Cr(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 60°. Se(1) is bonded to three equivalent Cr(1) and one Hg(1) atom to form a mixture of distorted edge and corner-sharing SeCr3Hg tetrahedra. is represented by the CIF file [CIF]
data_Cr2HgSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.664
_cell_length_b   7.664
_cell_length_c   7.664
_cell_angle_alpha   60.000
_cell_angle_beta   60.000
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   318.290
_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
  Cr  Cr0  1  0.125  0.125  0.125  1.0
  Cr  Cr1  1  0.625  0.125  0.125  1.0
  Cr  Cr2  1  0.125  0.625  0.125  1.0
  Cr  Cr3  1  0.125  0.125  0.625  1.0
  Hg  Hg4  1  0.500  0.500  0.500  1.0
  Hg  Hg5  1  0.750  0.750  0.750  1.0
  Se  Se6  1  0.360  0.360  0.360  1.0
  Se  Se7  1  0.921  0.360  0.360  1.0
  Se  Se8  1  0.890  0.890  0.890  1.0
  Se  Se9  1  0.360  0.360  0.921  1.0
  Se  Se10  1  0.360  0.921  0.360  1.0
  Se  Se11  1  0.890  0.890  0.329  1.0
  Se  Se12  1  0.890  0.329  0.890  1.0
  Se  Se13  1  0.329  0.890  0.890  1.0
[/CIF]
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