The structure described by CuCr2Se3Br is Spinel-derived structured and crystallizes in the trigonal R-3m space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to six equivalent Se(1) atoms to form CrSe6 octahedra that share corners with six equivalent Cu(1)Se3Br tetrahedra and edges with six equivalent Cr(2)Se4Br2 octahedra. In the second Cr site, Cr(2) is bonded to four equivalent Se(1) and two equivalent Br(1) atoms to form CrSe4Br2 octahedra that share corners with six equivalent Cu(1)Se3Br tetrahedra, edges with two equivalent Cr(1)Se6 octahedra, and edges with four equivalent Cr(2)Se4Br2 octahedra. Cu(1) is bonded to three equivalent Se(1) and one Br(1) atom to form CuSe3Br tetrahedra that share corners with three equivalent Cr(1)Se6 octahedra and corners with nine equivalent Cr(2)Se4Br2 octahedra. The corner-sharing octahedral tilt angles range from 53-61°. Se(1) is bonded in a rectangular see-saw-like geometry to one Cr(1), two equivalent Cr(2), and one Cu(1) atom. Br(1) is bonded in a rectangular see-saw-like geometry to three equivalent Cr(2) and one Cu(1) atom. is represented by the CIF file [CIF]
data_Cr2CuSe3Br
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.454
_cell_length_b   7.454
_cell_length_c   7.454
_cell_angle_alpha   59.965
_cell_angle_beta   59.965
_cell_angle_gamma   59.965
_symmetry_Int_Tables_number   1
_cell_volume   292.662
_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  0.500  0.500  0.500  1.0
  Cr  Cr1  1  0.500  0.000  0.500  1.0
  Cr  Cr2  1  0.000  0.500  0.500  1.0
  Cr  Cr3  1  0.500  0.500  0.000  1.0
  Cu  Cu4  1  0.112  0.112  0.112  1.0
  Cu  Cu5  1  0.888  0.888  0.888  1.0
  Se  Se6  1  0.740  0.279  0.740  1.0
  Se  Se7  1  0.279  0.740  0.740  1.0
  Se  Se8  1  0.740  0.740  0.279  1.0
  Se  Se9  1  0.260  0.721  0.260  1.0
  Se  Se10  1  0.721  0.260  0.260  1.0
  Se  Se11  1  0.260  0.260  0.721  1.0
  Br  Br12  1  0.745  0.745  0.745  1.0
  Br  Br13  1  0.255  0.255  0.255  1.0
[/CIF]
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The structure described by CuCr2Se3Br is Spinel-derived structured and crystallizes in the trigonal R-3m space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to six equivalent Se(1) atoms to form CrSe6 octahedra that share corners with six equivalent Cu(1)Se3Br tetrahedra and edges with six equivalent Cr(2)Se4Br2 octahedra. In the second Cr site, Cr(2) is bonded to four equivalent Se(1) and two equivalent Br(1) atoms to form CrSe4Br2 octahedra that share corners with six equivalent Cu(1)Se3Br tetrahedra, edges with two equivalent Cr(1)Se6 octahedra, and edges with four equivalent Cr(2)Se4Br2 octahedra. Cu(1) is bonded to three equivalent Se(1) and one Br(1) atom to form CuSe3Br tetrahedra that share corners with three equivalent Cr(1)Se6 octahedra and corners with nine equivalent Cr(2)Se4Br2 octahedra. The corner-sharing octahedral tilt angles range from 53-61°. Se(1) is bonded in a rectangular see-saw-like geometry to one Cr(1), two equivalent Cr(2), and one Cu(1) atom. Br(1) is bonded in a rectangular see-saw-like geometry to three equivalent Cr(2) and one Cu(1) atom. is represented by the CIF file [CIF]
data_Cr2CuSe3Br
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.454
_cell_length_b   7.454
_cell_length_c   7.454
_cell_angle_alpha   59.965
_cell_angle_beta   59.965
_cell_angle_gamma   59.965
_symmetry_Int_Tables_number   1
_cell_volume   292.662
_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  0.500  0.500  0.500  1.0
  Cr  Cr1  1  0.500  0.000  0.500  1.0
  Cr  Cr2  1  0.000  0.500  0.500  1.0
  Cr  Cr3  1  0.500  0.500  0.000  1.0
  Cu  Cu4  1  0.112  0.112  0.112  1.0
  Cu  Cu5  1  0.888  0.888  0.888  1.0
  Se  Se6  1  0.740  0.279  0.740  1.0
  Se  Se7  1  0.279  0.740  0.740  1.0
  Se  Se8  1  0.740  0.740  0.279  1.0
  Se  Se9  1  0.260  0.721  0.260  1.0
  Se  Se10  1  0.721  0.260  0.260  1.0
  Se  Se11  1  0.260  0.260  0.721  1.0
  Br  Br12  1  0.745  0.745  0.745  1.0
  Br  Br13  1  0.255  0.255  0.255  1.0
[/CIF]
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