The structure described by BaCu2SnSe4 crystallizes in the orthorhombic Ama2 space group. Ba(1) is bonded in a 8-coordinate geometry to two equivalent Se(1), two equivalent Se(2), and four equivalent Se(3) atoms. Cu(1) is bonded to one Se(1), one Se(2), and two equivalent Se(3) atoms to form distorted CuSe4 tetrahedra that share corners with two equivalent Cu(1)Se4 tetrahedra, corners with four equivalent Sn(1)Se4 tetrahedra, and  an edgeedge with one Cu(1)Se4 tetrahedra. Sn(1) is bonded to one Se(1), one Se(2), and two equivalent Se(3) atoms to form SnSe4 tetrahedra that share corners with eight equivalent Cu(1)Se4 tetrahedra. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Ba(1), two equivalent Cu(1), and one Sn(1) atom to form distorted corner-sharing SeBa2Cu2Sn trigonal bipyramids. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to two equivalent Ba(1), two equivalent Cu(1), and one Sn(1) atom. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to two equivalent Ba(1), two equivalent Cu(1), and one Sn(1) atom. is represented by the CIF card [CIF]
data_BaCu2SnSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.656
_cell_length_b   6.656
_cell_length_c   11.214
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   118.159
_symmetry_Int_Tables_number   1
_cell_volume   437.990
_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
  Ba  Ba0  1  0.632  0.632  0.500  1.0
  Ba  Ba1  1  0.632  0.632  0.000  1.0
  Cu  Cu2  1  0.008  0.449  0.130  1.0
  Cu  Cu3  1  0.008  0.449  0.370  1.0
  Cu  Cu4  1  0.449  0.008  0.630  1.0
  Cu  Cu5  1  0.449  0.008  0.870  1.0
  Sn  Sn6  1  0.379  0.081  0.250  1.0
  Sn  Sn7  1  0.081  0.379  0.750  1.0
  Se  Se8  1  0.441  0.317  0.750  1.0
  Se  Se9  1  0.969  0.744  0.250  1.0
  Se  Se10  1  0.317  0.441  0.250  1.0
  Se  Se11  1  0.744  0.969  0.750  1.0
  Se  Se12  1  0.133  0.642  0.931  1.0
  Se  Se13  1  0.642  0.133  0.069  1.0
  Se  Se14  1  0.133  0.642  0.569  1.0
  Se  Se15  1  0.642  0.133  0.431  1.0
[/CIF]
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The structure described by BaCu2SnSe4 crystallizes in the orthorhombic Ama2 space group. Ba(1) is bonded in a 8-coordinate geometry to two equivalent Se(1), two equivalent Se(2), and four equivalent Se(3) atoms. Cu(1) is bonded to one Se(1), one Se(2), and two equivalent Se(3) atoms to form distorted CuSe4 tetrahedra that share corners with two equivalent Cu(1)Se4 tetrahedra, corners with four equivalent Sn(1)Se4 tetrahedra, and  an edgeedge with one Cu(1)Se4 tetrahedra. Sn(1) is bonded to one Se(1), one Se(2), and two equivalent Se(3) atoms to form SnSe4 tetrahedra that share corners with eight equivalent Cu(1)Se4 tetrahedra. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Ba(1), two equivalent Cu(1), and one Sn(1) atom to form distorted corner-sharing SeBa2Cu2Sn trigonal bipyramids. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to two equivalent Ba(1), two equivalent Cu(1), and one Sn(1) atom. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to two equivalent Ba(1), two equivalent Cu(1), and one Sn(1) atom. is represented by the CIF card [CIF]
data_BaCu2SnSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.656
_cell_length_b   6.656
_cell_length_c   11.214
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   118.159
_symmetry_Int_Tables_number   1
_cell_volume   437.990
_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
  Ba  Ba0  1  0.632  0.632  0.500  1.0
  Ba  Ba1  1  0.632  0.632  0.000  1.0
  Cu  Cu2  1  0.008  0.449  0.130  1.0
  Cu  Cu3  1  0.008  0.449  0.370  1.0
  Cu  Cu4  1  0.449  0.008  0.630  1.0
  Cu  Cu5  1  0.449  0.008  0.870  1.0
  Sn  Sn6  1  0.379  0.081  0.250  1.0
  Sn  Sn7  1  0.081  0.379  0.750  1.0
  Se  Se8  1  0.441  0.317  0.750  1.0
  Se  Se9  1  0.969  0.744  0.250  1.0
  Se  Se10  1  0.317  0.441  0.250  1.0
  Se  Se11  1  0.744  0.969  0.750  1.0
  Se  Se12  1  0.133  0.642  0.931  1.0
  Se  Se13  1  0.642  0.133  0.069  1.0
  Se  Se14  1  0.133  0.642  0.569  1.0
  Se  Se15  1  0.642  0.133  0.431  1.0
[/CIF]
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