The material described by Cu2FeSiSe4 is Stannite structured and crystallizes in the tetragonal I-42m space group. Fe(1) is bonded to four equivalent Se(1) atoms to form FeSe4 tetrahedra that share corners with four equivalent Si(1)Se4 tetrahedra and corners with eight equivalent Cu(1)Se4 tetrahedra. Cu(1) is bonded to four equivalent Se(1) atoms to form CuSe4 tetrahedra that share corners with four equivalent Fe(1)Se4 tetrahedra, corners with four equivalent Cu(1)Se4 tetrahedra, and corners with four equivalent Si(1)Se4 tetrahedra. Si(1) is bonded to four equivalent Se(1) atoms to form SiSe4 tetrahedra that share corners with four equivalent Fe(1)Se4 tetrahedra and corners with eight equivalent Cu(1)Se4 tetrahedra. Se(1) is bonded to one Fe(1), two equivalent Cu(1), and one Si(1) atom to form corner-sharing SeFeCu2Si tetrahedra. is represented by the CIF card [CIF]
data_FeCu2SiSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.788
_cell_length_b   6.788
_cell_length_c   6.788
_cell_angle_alpha   131.395
_cell_angle_beta   131.395
_cell_angle_gamma   71.186
_symmetry_Int_Tables_number   1
_cell_volume   172.297
_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
  Fe  Fe0  1  0.000  0.000  0.000  1.0
  Cu  Cu1  1  0.250  0.750  0.500  1.0
  Cu  Cu2  1  0.750  0.250  0.500  1.0
  Si  Si3  1  0.500  0.500  0.000  1.0
  Se  Se4  1  0.866  0.381  0.000  1.0
  Se  Se5  1  0.381  0.866  0.000  1.0
  Se  Se6  1  0.619  0.619  0.485  1.0
  Se  Se7  1  0.134  0.134  0.515  1.0
[/CIF]
.
The material described by Cu2FeSiSe4 is Stannite structured and crystallizes in the tetragonal I-42m space group. Fe(1) is bonded to four equivalent Se(1) atoms to form FeSe4 tetrahedra that share corners with four equivalent Si(1)Se4 tetrahedra and corners with eight equivalent Cu(1)Se4 tetrahedra. Cu(1) is bonded to four equivalent Se(1) atoms to form CuSe4 tetrahedra that share corners with four equivalent Fe(1)Se4 tetrahedra, corners with four equivalent Cu(1)Se4 tetrahedra, and corners with four equivalent Si(1)Se4 tetrahedra. Si(1) is bonded to four equivalent Se(1) atoms to form SiSe4 tetrahedra that share corners with four equivalent Fe(1)Se4 tetrahedra and corners with eight equivalent Cu(1)Se4 tetrahedra. Se(1) is bonded to one Fe(1), two equivalent Cu(1), and one Si(1) atom to form corner-sharing SeFeCu2Si tetrahedra. is represented by the CIF card [CIF]
data_FeCu2SiSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.788
_cell_length_b   6.788
_cell_length_c   6.788
_cell_angle_alpha   131.395
_cell_angle_beta   131.395
_cell_angle_gamma   71.186
_symmetry_Int_Tables_number   1
_cell_volume   172.297
_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
  Fe  Fe0  1  0.000  0.000  0.000  1.0
  Cu  Cu1  1  0.250  0.750  0.500  1.0
  Cu  Cu2  1  0.750  0.250  0.500  1.0
  Si  Si3  1  0.500  0.500  0.000  1.0
  Se  Se4  1  0.866  0.381  0.000  1.0
  Se  Se5  1  0.381  0.866  0.000  1.0
  Se  Se6  1  0.619  0.619  0.485  1.0
  Se  Se7  1  0.134  0.134  0.515  1.0
[/CIF]
.