The material described by Hg5Ga2Se8 crystallizes in the tetragonal I-4m2 space group. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded to four equivalent Se(2) atoms to form HgSe4 tetrahedra that share corners with four equivalent Ga(1)Se4 tetrahedra and corners with eight equivalent Hg(2)Se4 tetrahedra. In the second Hg site, Hg(2) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form HgSe4 tetrahedra that share corners with two equivalent Hg(1)Se4 tetrahedra, corners with four equivalent Hg(2)Se4 tetrahedra, and corners with four equivalent Ga(1)Se4 tetrahedra. Ga(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form GaSe4 tetrahedra that share corners with two equivalent Hg(1)Se4 tetrahedra and corners with eight equivalent Hg(2)Se4 tetrahedra. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a trigonal non-coplanar geometry to two equivalent Hg(2) and one Ga(1) atom. In the second Se site, Se(2) is bonded to one Hg(1), two equivalent Hg(2), and one Ga(1) atom to form corner-sharing SeGaHg3 tetrahedra. is represented by the CIF file [CIF]
data_Ga2Hg5Se8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.470
_cell_length_b   8.470
_cell_length_c   8.470
_cell_angle_alpha   119.043
_cell_angle_beta   119.043
_cell_angle_gamma   91.666
_symmetry_Int_Tables_number   1
_cell_volume   435.638
_cell_formula_units_Z   1
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
  Ga  Ga0  1  0.237  0.237  0.000  1.0
  Ga  Ga1  1  0.762  0.762  0.000  1.0
  Hg  Hg2  1  0.250  0.750  0.500  1.0
  Hg  Hg3  1  0.765  0.235  0.000  1.0
  Hg  Hg4  1  0.235  0.765  0.000  1.0
  Hg  Hg5  1  0.765  0.765  0.530  1.0
  Hg  Hg6  1  0.235  0.235  0.470  1.0
  Se  Se7  1  0.892  0.147  0.745  1.0
  Se  Se8  1  0.402  0.147  0.255  1.0
  Se  Se9  1  0.853  0.598  0.745  1.0
  Se  Se10  1  0.853  0.108  0.255  1.0
  Se  Se11  1  0.401  0.631  0.770  1.0
  Se  Se12  1  0.862  0.631  0.230  1.0
  Se  Se13  1  0.369  0.138  0.770  1.0
  Se  Se14  1  0.369  0.599  0.230  1.0
[/CIF]
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The material described by Hg5Ga2Se8 crystallizes in the tetragonal I-4m2 space group. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded to four equivalent Se(2) atoms to form HgSe4 tetrahedra that share corners with four equivalent Ga(1)Se4 tetrahedra and corners with eight equivalent Hg(2)Se4 tetrahedra. In the second Hg site, Hg(2) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form HgSe4 tetrahedra that share corners with two equivalent Hg(1)Se4 tetrahedra, corners with four equivalent Hg(2)Se4 tetrahedra, and corners with four equivalent Ga(1)Se4 tetrahedra. Ga(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form GaSe4 tetrahedra that share corners with two equivalent Hg(1)Se4 tetrahedra and corners with eight equivalent Hg(2)Se4 tetrahedra. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a trigonal non-coplanar geometry to two equivalent Hg(2) and one Ga(1) atom. In the second Se site, Se(2) is bonded to one Hg(1), two equivalent Hg(2), and one Ga(1) atom to form corner-sharing SeGaHg3 tetrahedra. is represented by the CIF file [CIF]
data_Ga2Hg5Se8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.470
_cell_length_b   8.470
_cell_length_c   8.470
_cell_angle_alpha   119.043
_cell_angle_beta   119.043
_cell_angle_gamma   91.666
_symmetry_Int_Tables_number   1
_cell_volume   435.638
_cell_formula_units_Z   1
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
  Ga  Ga0  1  0.237  0.237  0.000  1.0
  Ga  Ga1  1  0.762  0.762  0.000  1.0
  Hg  Hg2  1  0.250  0.750  0.500  1.0
  Hg  Hg3  1  0.765  0.235  0.000  1.0
  Hg  Hg4  1  0.235  0.765  0.000  1.0
  Hg  Hg5  1  0.765  0.765  0.530  1.0
  Hg  Hg6  1  0.235  0.235  0.470  1.0
  Se  Se7  1  0.892  0.147  0.745  1.0
  Se  Se8  1  0.402  0.147  0.255  1.0
  Se  Se9  1  0.853  0.598  0.745  1.0
  Se  Se10  1  0.853  0.108  0.255  1.0
  Se  Se11  1  0.401  0.631  0.770  1.0
  Se  Se12  1  0.862  0.631  0.230  1.0
  Se  Se13  1  0.369  0.138  0.770  1.0
  Se  Se14  1  0.369  0.599  0.230  1.0
[/CIF]
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