The crystal structure described by K2CuGa3Se6 crystallizes in the monoclinic C2/c space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one Se(1), one Se(2), one Se(3), one Se(5), one Se(6), and two equivalent Se(4) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one Se(1), one Se(3), one Se(4), one Se(5), one Se(6), and two equivalent Se(2) atoms. Cu(1) is bonded to one Se(1), one Se(3), one Se(5), and one Se(6) atom to form CuSe4 tetrahedra that share corners with two equivalent Ga(1)Se4 tetrahedra, corners with two equivalent Ga(2)Se4 tetrahedra, corners with two equivalent Ga(3)Se4 tetrahedra, and corners with two equivalent Ga(4)Se4 tetrahedra. There are four inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one Se(2), one Se(4), one Se(5), and one Se(6) atom to form GaSe4 tetrahedra that share  a cornercorner with one Ga(3)Se4 tetrahedra,  a cornercorner with one Ga(4)Se4 tetrahedra, corners with two equivalent Cu(1)Se4 tetrahedra, and corners with two equivalent Ga(2)Se4 tetrahedra. In the second Ga site, Ga(2) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form GaSe4 tetrahedra that share  a cornercorner with one Ga(3)Se4 tetrahedra,  a cornercorner with one Ga(4)Se4 tetrahedra, corners with two equivalent Cu(1)Se4 tetrahedra, and corners with two equivalent Ga(1)Se4 tetrahedra. In the third Ga site, Ga(3) is bonded to two equivalent Se(3) and two equivalent Se(6) atoms to form GaSe4 tetrahedra that share corners with two equivalent Ga(1)Se4 tetrahedra, corners with two equivalent Ga(2)Se4 tetrahedra, and corners with four equivalent Cu(1)Se4 tetrahedra. In the fourth Ga site, Ga(4) is bonded to two equivalent Se(1) and two equivalent Se(5) atoms to form GaSe4 tetrahedra that share corners with two equivalent Ga(1)Se4 tetrahedra, corners with two equivalent Ga(2)Se4 tetrahedra, and corners with four equivalent Cu(1)Se4 tetrahedra. There are six inequivalent Se sites. In the first Se site, Se(6) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Cu(1), one Ga(1), and one Ga(3) atom. In the second Se site, Se(1) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Cu(1), one Ga(2), and one Ga(4) atom. In the third Se site, Se(2) is bonded in a 5-coordinate geometry to one K(1), two equivalent K(2), one Ga(1), and one Ga(2) atom. In the fourth Se site, Se(3) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Cu(1), one Ga(2), and one Ga(3) atom. In the fifth Se site, Se(4) is bonded in a 5-coordinate geometry to one K(2), two equivalent K(1), one Ga(1), and one Ga(2) atom. In the sixth Se site, Se(5) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Cu(1), one Ga(1), and one Ga(4) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_K2Ga3CuSe6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.917
_cell_length_b   7.917
_cell_length_c   21.144
_cell_angle_alpha   84.630
_cell_angle_beta   84.630
_cell_angle_gamma   90.137
_symmetry_Int_Tables_number   1
_cell_volume   1313.662
_cell_formula_units_Z   4
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
  K  K0  1  0.777  0.393  0.420  1.0
  K  K1  1  0.236  0.104  0.580  1.0
  K  K2  1  0.104  0.236  0.080  1.0
  K  K3  1  0.764  0.896  0.420  1.0
  K  K4  1  0.393  0.777  0.920  1.0
  K  K5  1  0.223  0.607  0.580  1.0
  K  K6  1  0.896  0.764  0.920  1.0
  K  K7  1  0.607  0.223  0.080  1.0
  Ga  Ga8  1  0.155  0.281  0.879  1.0
  Ga  Ga9  1  0.845  0.719  0.121  1.0
  Ga  Ga10  1  0.719  0.845  0.621  1.0
  Ga  Ga11  1  0.346  0.720  0.120  1.0
  Ga  Ga12  1  0.280  0.654  0.380  1.0
  Ga  Ga13  1  0.654  0.280  0.880  1.0
  Ga  Ga14  1  0.720  0.346  0.620  1.0
  Ga  Ga15  1  0.558  0.442  0.250  1.0
  Ga  Ga16  1  0.442  0.558  0.750  1.0
  Ga  Ga17  1  0.068  0.932  0.250  1.0
  Ga  Ga18  1  0.281  0.155  0.379  1.0
  Ga  Ga19  1  0.932  0.068  0.750  1.0
  Cu  Cu20  1  0.065  0.438  0.250  1.0
  Cu  Cu21  1  0.562  0.935  0.250  1.0
  Cu  Cu22  1  0.935  0.562  0.750  1.0
  Cu  Cu23  1  0.438  0.065  0.750  1.0
  Se  Se24  1  0.332  0.966  0.181  1.0
  Se  Se25  1  0.710  0.112  0.551  1.0
  Se  Se26  1  0.112  0.710  0.051  1.0
  Se  Se27  1  0.290  0.888  0.449  1.0
  Se  Se28  1  0.442  0.329  0.680  1.0
  Se  Se29  1  0.671  0.558  0.820  1.0
  Se  Se30  1  0.558  0.671  0.320  1.0
  Se  Se31  1  0.329  0.442  0.180  1.0
  Se  Se32  1  0.386  0.236  0.950  1.0
  Se  Se33  1  0.764  0.614  0.550  1.0
  Se  Se34  1  0.614  0.764  0.050  1.0
  Se  Se35  1  0.236  0.386  0.450  1.0
  Se  Se36  1  0.168  0.035  0.818  1.0
  Se  Se37  1  0.965  0.832  0.682  1.0
  Se  Se38  1  0.832  0.965  0.182  1.0
  Se  Se39  1  0.035  0.168  0.318  1.0
  Se  Se40  1  0.034  0.668  0.319  1.0
  Se  Se41  1  0.668  0.034  0.819  1.0
  Se  Se42  1  0.966  0.332  0.681  1.0
  Se  Se43  1  0.557  0.172  0.318  1.0
  Se  Se44  1  0.828  0.443  0.182  1.0
  Se  Se45  1  0.443  0.828  0.682  1.0
  Se  Se46  1  0.172  0.557  0.818  1.0
  Se  Se47  1  0.888  0.290  0.949  1.0
[/CIF]
.
The crystal structure described by K2CuGa3Se6 crystallizes in the monoclinic C2/c space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one Se(1), one Se(2), one Se(3), one Se(5), one Se(6), and two equivalent Se(4) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one Se(1), one Se(3), one Se(4), one Se(5), one Se(6), and two equivalent Se(2) atoms. Cu(1) is bonded to one Se(1), one Se(3), one Se(5), and one Se(6) atom to form CuSe4 tetrahedra that share corners with two equivalent Ga(1)Se4 tetrahedra, corners with two equivalent Ga(2)Se4 tetrahedra, corners with two equivalent Ga(3)Se4 tetrahedra, and corners with two equivalent Ga(4)Se4 tetrahedra. There are four inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one Se(2), one Se(4), one Se(5), and one Se(6) atom to form GaSe4 tetrahedra that share  a cornercorner with one Ga(3)Se4 tetrahedra,  a cornercorner with one Ga(4)Se4 tetrahedra, corners with two equivalent Cu(1)Se4 tetrahedra, and corners with two equivalent Ga(2)Se4 tetrahedra. In the second Ga site, Ga(2) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form GaSe4 tetrahedra that share  a cornercorner with one Ga(3)Se4 tetrahedra,  a cornercorner with one Ga(4)Se4 tetrahedra, corners with two equivalent Cu(1)Se4 tetrahedra, and corners with two equivalent Ga(1)Se4 tetrahedra. In the third Ga site, Ga(3) is bonded to two equivalent Se(3) and two equivalent Se(6) atoms to form GaSe4 tetrahedra that share corners with two equivalent Ga(1)Se4 tetrahedra, corners with two equivalent Ga(2)Se4 tetrahedra, and corners with four equivalent Cu(1)Se4 tetrahedra. In the fourth Ga site, Ga(4) is bonded to two equivalent Se(1) and two equivalent Se(5) atoms to form GaSe4 tetrahedra that share corners with two equivalent Ga(1)Se4 tetrahedra, corners with two equivalent Ga(2)Se4 tetrahedra, and corners with four equivalent Cu(1)Se4 tetrahedra. There are six inequivalent Se sites. In the first Se site, Se(6) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Cu(1), one Ga(1), and one Ga(3) atom. In the second Se site, Se(1) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Cu(1), one Ga(2), and one Ga(4) atom. In the third Se site, Se(2) is bonded in a 5-coordinate geometry to one K(1), two equivalent K(2), one Ga(1), and one Ga(2) atom. In the fourth Se site, Se(3) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Cu(1), one Ga(2), and one Ga(3) atom. In the fifth Se site, Se(4) is bonded in a 5-coordinate geometry to one K(2), two equivalent K(1), one Ga(1), and one Ga(2) atom. In the sixth Se site, Se(5) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Cu(1), one Ga(1), and one Ga(4) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_K2Ga3CuSe6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.917
_cell_length_b   7.917
_cell_length_c   21.144
_cell_angle_alpha   84.630
_cell_angle_beta   84.630
_cell_angle_gamma   90.137
_symmetry_Int_Tables_number   1
_cell_volume   1313.662
_cell_formula_units_Z   4
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
  K  K0  1  0.777  0.393  0.420  1.0
  K  K1  1  0.236  0.104  0.580  1.0
  K  K2  1  0.104  0.236  0.080  1.0
  K  K3  1  0.764  0.896  0.420  1.0
  K  K4  1  0.393  0.777  0.920  1.0
  K  K5  1  0.223  0.607  0.580  1.0
  K  K6  1  0.896  0.764  0.920  1.0
  K  K7  1  0.607  0.223  0.080  1.0
  Ga  Ga8  1  0.155  0.281  0.879  1.0
  Ga  Ga9  1  0.845  0.719  0.121  1.0
  Ga  Ga10  1  0.719  0.845  0.621  1.0
  Ga  Ga11  1  0.346  0.720  0.120  1.0
  Ga  Ga12  1  0.280  0.654  0.380  1.0
  Ga  Ga13  1  0.654  0.280  0.880  1.0
  Ga  Ga14  1  0.720  0.346  0.620  1.0
  Ga  Ga15  1  0.558  0.442  0.250  1.0
  Ga  Ga16  1  0.442  0.558  0.750  1.0
  Ga  Ga17  1  0.068  0.932  0.250  1.0
  Ga  Ga18  1  0.281  0.155  0.379  1.0
  Ga  Ga19  1  0.932  0.068  0.750  1.0
  Cu  Cu20  1  0.065  0.438  0.250  1.0
  Cu  Cu21  1  0.562  0.935  0.250  1.0
  Cu  Cu22  1  0.935  0.562  0.750  1.0
  Cu  Cu23  1  0.438  0.065  0.750  1.0
  Se  Se24  1  0.332  0.966  0.181  1.0
  Se  Se25  1  0.710  0.112  0.551  1.0
  Se  Se26  1  0.112  0.710  0.051  1.0
  Se  Se27  1  0.290  0.888  0.449  1.0
  Se  Se28  1  0.442  0.329  0.680  1.0
  Se  Se29  1  0.671  0.558  0.820  1.0
  Se  Se30  1  0.558  0.671  0.320  1.0
  Se  Se31  1  0.329  0.442  0.180  1.0
  Se  Se32  1  0.386  0.236  0.950  1.0
  Se  Se33  1  0.764  0.614  0.550  1.0
  Se  Se34  1  0.614  0.764  0.050  1.0
  Se  Se35  1  0.236  0.386  0.450  1.0
  Se  Se36  1  0.168  0.035  0.818  1.0
  Se  Se37  1  0.965  0.832  0.682  1.0
  Se  Se38  1  0.832  0.965  0.182  1.0
  Se  Se39  1  0.035  0.168  0.318  1.0
  Se  Se40  1  0.034  0.668  0.319  1.0
  Se  Se41  1  0.668  0.034  0.819  1.0
  Se  Se42  1  0.966  0.332  0.681  1.0
  Se  Se43  1  0.557  0.172  0.318  1.0
  Se  Se44  1  0.828  0.443  0.182  1.0
  Se  Se45  1  0.443  0.828  0.682  1.0
  Se  Se46  1  0.172  0.557  0.818  1.0
  Se  Se47  1  0.888  0.290  0.949  1.0
[/CIF]
.