The compound described by Cu2SiSe3 is Enargite-like structured and crystallizes in the monoclinic Cc space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one Se(1), one Se(3), and two equivalent Se(2) atoms to form CuSe4 tetrahedra that share corners with two equivalent Cu(1)Se4 tetrahedra, corners with five equivalent Cu(2)Se4 tetrahedra, and corners with five equivalent Si(1)Se4 tetrahedra. In the second Cu site, Cu(2) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form CuSe4 tetrahedra that share corners with two equivalent Cu(2)Se4 tetrahedra, corners with five equivalent Cu(1)Se4 tetrahedra, and corners with five equivalent Si(1)Se4 tetrahedra. Si(1) is bonded to one Se(1), one Se(2), and two equivalent Se(3) atoms to form SiSe4 tetrahedra that share corners with two equivalent Si(1)Se4 tetrahedra, corners with five equivalent Cu(1)Se4 tetrahedra, and corners with five equivalent Cu(2)Se4 tetrahedra. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Cu(1), two equivalent Cu(2), and one Si(1) atom to form SeCu3Si tetrahedra that share corners with two equivalent Se(1)Cu3Si tetrahedra, corners with five equivalent Se(3)Cu2Si2 tetrahedra, and corners with five equivalent Se(2)Cu3Si tetrahedra. In the second Se site, Se(2) is bonded to one Cu(2), two equivalent Cu(1), and one Si(1) atom to form SeCu3Si tetrahedra that share corners with two equivalent Se(2)Cu3Si tetrahedra, corners with five equivalent Se(3)Cu2Si2 tetrahedra, and corners with five equivalent Se(1)Cu3Si tetrahedra. In the third Se site, Se(3) is bonded to one Cu(1), one Cu(2), and two equivalent Si(1) atoms to form SeCu2Si2 tetrahedra that share corners with two equivalent Se(3)Cu2Si2 tetrahedra, corners with five equivalent Se(1)Cu3Si tetrahedra, and corners with five equivalent Se(2)Cu3Si tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cu2SiSe3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.686
_cell_length_b   6.671
_cell_length_c   6.744
_cell_angle_alpha   60.359
_cell_angle_beta   80.987
_cell_angle_gamma   71.533
_symmetry_Int_Tables_number   1
_cell_volume   247.973
_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
  Cu  Cu0  1  0.503  0.233  0.510  1.0
  Cu  Cu1  1  0.003  0.743  0.490  1.0
  Cu  Cu2  1  0.500  0.584  0.826  1.0
  Cu  Cu3  1  0.000  0.410  0.174  1.0
  Si  Si4  1  0.524  0.886  0.170  1.0
  Si  Si5  1  0.024  0.055  0.830  1.0
  Se  Se6  1  0.123  0.699  0.831  1.0
  Se  Se7  1  0.623  0.529  0.169  1.0
  Se  Se8  1  0.627  0.867  0.484  1.0
  Se  Se9  1  0.127  0.351  0.516  1.0
  Se  Se10  1  0.145  0.031  0.157  1.0
  Se  Se11  1  0.645  0.188  0.843  1.0
[/CIF]
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The compound described by Cu2SiSe3 is Enargite-like structured and crystallizes in the monoclinic Cc space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one Se(1), one Se(3), and two equivalent Se(2) atoms to form CuSe4 tetrahedra that share corners with two equivalent Cu(1)Se4 tetrahedra, corners with five equivalent Cu(2)Se4 tetrahedra, and corners with five equivalent Si(1)Se4 tetrahedra. In the second Cu site, Cu(2) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form CuSe4 tetrahedra that share corners with two equivalent Cu(2)Se4 tetrahedra, corners with five equivalent Cu(1)Se4 tetrahedra, and corners with five equivalent Si(1)Se4 tetrahedra. Si(1) is bonded to one Se(1), one Se(2), and two equivalent Se(3) atoms to form SiSe4 tetrahedra that share corners with two equivalent Si(1)Se4 tetrahedra, corners with five equivalent Cu(1)Se4 tetrahedra, and corners with five equivalent Cu(2)Se4 tetrahedra. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Cu(1), two equivalent Cu(2), and one Si(1) atom to form SeCu3Si tetrahedra that share corners with two equivalent Se(1)Cu3Si tetrahedra, corners with five equivalent Se(3)Cu2Si2 tetrahedra, and corners with five equivalent Se(2)Cu3Si tetrahedra. In the second Se site, Se(2) is bonded to one Cu(2), two equivalent Cu(1), and one Si(1) atom to form SeCu3Si tetrahedra that share corners with two equivalent Se(2)Cu3Si tetrahedra, corners with five equivalent Se(3)Cu2Si2 tetrahedra, and corners with five equivalent Se(1)Cu3Si tetrahedra. In the third Se site, Se(3) is bonded to one Cu(1), one Cu(2), and two equivalent Si(1) atoms to form SeCu2Si2 tetrahedra that share corners with two equivalent Se(3)Cu2Si2 tetrahedra, corners with five equivalent Se(1)Cu3Si tetrahedra, and corners with five equivalent Se(2)Cu3Si tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cu2SiSe3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.686
_cell_length_b   6.671
_cell_length_c   6.744
_cell_angle_alpha   60.359
_cell_angle_beta   80.987
_cell_angle_gamma   71.533
_symmetry_Int_Tables_number   1
_cell_volume   247.973
_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
  Cu  Cu0  1  0.503  0.233  0.510  1.0
  Cu  Cu1  1  0.003  0.743  0.490  1.0
  Cu  Cu2  1  0.500  0.584  0.826  1.0
  Cu  Cu3  1  0.000  0.410  0.174  1.0
  Si  Si4  1  0.524  0.886  0.170  1.0
  Si  Si5  1  0.024  0.055  0.830  1.0
  Se  Se6  1  0.123  0.699  0.831  1.0
  Se  Se7  1  0.623  0.529  0.169  1.0
  Se  Se8  1  0.627  0.867  0.484  1.0
  Se  Se9  1  0.127  0.351  0.516  1.0
  Se  Se10  1  0.145  0.031  0.157  1.0
  Se  Se11  1  0.645  0.188  0.843  1.0
[/CIF]
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