The crystal structure described by K2CuIn3Se6 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 6-coordinate geometry to one Se(1), one Se(2), one Se(3), one Se(4), one Se(5), and one Se(6) atom. In the second K site, K(2) is bonded in a 6-coordinate geometry to one Se(1), one Se(2), one Se(3), one Se(4), one Se(5), and one Se(6) atom. Cu(1) is bonded to one Se(1), one Se(2), one Se(3), and one Se(5) atom to form CuSe4 tetrahedra that share corners with two equivalent In(1)Se4 tetrahedra, corners with two equivalent In(2)Se4 tetrahedra, corners with two equivalent In(3)Se4 tetrahedra, and corners with two equivalent In(4)Se4 tetrahedra. There are four inequivalent In sites. In the first In site, In(1) is bonded to one Se(1), one Se(2), one Se(4), and one Se(6) atom to form InSe4 tetrahedra that share  a cornercorner with one In(3)Se4 tetrahedra,  a cornercorner with one In(4)Se4 tetrahedra, corners with two equivalent Cu(1)Se4 tetrahedra, and corners with two equivalent In(2)Se4 tetrahedra. In the second In site, In(2) is bonded to one Se(3), one Se(4), one Se(5), and one Se(6) atom to form InSe4 tetrahedra that share  a cornercorner with one In(3)Se4 tetrahedra,  a cornercorner with one In(4)Se4 tetrahedra, corners with two equivalent Cu(1)Se4 tetrahedra, and corners with two equivalent In(1)Se4 tetrahedra. In the third In site, In(3) is bonded to two equivalent Se(2) and two equivalent Se(5) atoms to form InSe4 tetrahedra that share corners with two equivalent In(1)Se4 tetrahedra, corners with two equivalent In(2)Se4 tetrahedra, and corners with four equivalent Cu(1)Se4 tetrahedra. In the fourth In site, In(4) is bonded to two equivalent Se(1) and two equivalent Se(3) atoms to form InSe4 tetrahedra that share corners with two equivalent In(1)Se4 tetrahedra, corners with two equivalent In(2)Se4 tetrahedra, and corners with four equivalent Cu(1)Se4 tetrahedra. There are six inequivalent Se sites. In the first Se site, Se(5) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Cu(1), one In(2), and one In(3) atom. In the second Se site, Se(3) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Cu(1), one In(2), and one In(4) atom. In the third Se site, Se(6) is bonded in a rectangular see-saw-like geometry to one K(1), one K(2), one In(1), and one In(2) atom. In the fourth Se site, Se(1) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Cu(1), one In(1), and one In(4) atom. In the fifth Se site, Se(2) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Cu(1), one In(1), and one In(3) atom. In the sixth Se site, Se(4) is bonded in a rectangular see-saw-like geometry to one K(1), one K(2), one In(1), and one In(2) atom. is represented by the CIF card [CIF]
data_K2In3CuSe6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.250
_cell_length_b   8.250
_cell_length_c   21.723
_cell_angle_alpha   84.600
_cell_angle_beta   84.600
_cell_angle_gamma   90.019
_symmetry_Int_Tables_number   1
_cell_volume   1465.322
_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  0.762  0.395  0.417  1.0
  K  K1  1  0.605  0.238  0.083  1.0
  K  K2  1  0.238  0.605  0.583  1.0
  K  K3  1  0.395  0.762  0.917  1.0
  K  K4  1  0.780  0.896  0.417  1.0
  K  K5  1  0.104  0.220  0.083  1.0
  K  K6  1  0.220  0.104  0.583  1.0
  K  K7  1  0.896  0.780  0.917  1.0
  In  In8  1  0.279  0.154  0.385  1.0
  In  In9  1  0.846  0.721  0.115  1.0
  In  In10  1  0.721  0.846  0.615  1.0
  In  In11  1  0.154  0.279  0.885  1.0
  In  In12  1  0.346  0.722  0.115  1.0
  In  In13  1  0.278  0.654  0.385  1.0
  In  In14  1  0.654  0.278  0.885  1.0
  In  In15  1  0.722  0.346  0.615  1.0
  In  In16  1  0.561  0.439  0.250  1.0
  In  In17  1  0.439  0.561  0.750  1.0
  In  In18  1  0.063  0.937  0.250  1.0
  In  In19  1  0.937  0.063  0.750  1.0
  Cu  Cu20  1  0.063  0.438  0.250  1.0
  Cu  Cu21  1  0.562  0.937  0.250  1.0
  Cu  Cu22  1  0.937  0.562  0.750  1.0
  Cu  Cu23  1  0.438  0.063  0.750  1.0
  Se  Se24  1  0.183  0.027  0.820  1.0
  Se  Se25  1  0.973  0.817  0.680  1.0
  Se  Se26  1  0.817  0.973  0.180  1.0
  Se  Se27  1  0.027  0.183  0.320  1.0
  Se  Se28  1  0.158  0.564  0.820  1.0
  Se  Se29  1  0.436  0.842  0.680  1.0
  Se  Se30  1  0.842  0.436  0.180  1.0
  Se  Se31  1  0.564  0.158  0.320  1.0
  Se  Se32  1  0.974  0.343  0.681  1.0
  Se  Se33  1  0.657  0.026  0.819  1.0
  Se  Se34  1  0.026  0.657  0.319  1.0
  Se  Se35  1  0.343  0.974  0.181  1.0
  Se  Se36  1  0.885  0.266  0.960  1.0
  Se  Se37  1  0.734  0.115  0.540  1.0
  Se  Se38  1  0.115  0.734  0.040  1.0
  Se  Se39  1  0.266  0.885  0.460  1.0
  Se  Se40  1  0.436  0.316  0.681  1.0
  Se  Se41  1  0.684  0.564  0.819  1.0
  Se  Se42  1  0.564  0.684  0.319  1.0
  Se  Se43  1  0.316  0.436  0.181  1.0
  Se  Se44  1  0.386  0.254  0.960  1.0
  Se  Se45  1  0.746  0.614  0.540  1.0
  Se  Se46  1  0.614  0.746  0.040  1.0
  Se  Se47  1  0.254  0.386  0.460  1.0
[/CIF]
.
The crystal structure described by K2CuIn3Se6 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 6-coordinate geometry to one Se(1), one Se(2), one Se(3), one Se(4), one Se(5), and one Se(6) atom. In the second K site, K(2) is bonded in a 6-coordinate geometry to one Se(1), one Se(2), one Se(3), one Se(4), one Se(5), and one Se(6) atom. Cu(1) is bonded to one Se(1), one Se(2), one Se(3), and one Se(5) atom to form CuSe4 tetrahedra that share corners with two equivalent In(1)Se4 tetrahedra, corners with two equivalent In(2)Se4 tetrahedra, corners with two equivalent In(3)Se4 tetrahedra, and corners with two equivalent In(4)Se4 tetrahedra. There are four inequivalent In sites. In the first In site, In(1) is bonded to one Se(1), one Se(2), one Se(4), and one Se(6) atom to form InSe4 tetrahedra that share  a cornercorner with one In(3)Se4 tetrahedra,  a cornercorner with one In(4)Se4 tetrahedra, corners with two equivalent Cu(1)Se4 tetrahedra, and corners with two equivalent In(2)Se4 tetrahedra. In the second In site, In(2) is bonded to one Se(3), one Se(4), one Se(5), and one Se(6) atom to form InSe4 tetrahedra that share  a cornercorner with one In(3)Se4 tetrahedra,  a cornercorner with one In(4)Se4 tetrahedra, corners with two equivalent Cu(1)Se4 tetrahedra, and corners with two equivalent In(1)Se4 tetrahedra. In the third In site, In(3) is bonded to two equivalent Se(2) and two equivalent Se(5) atoms to form InSe4 tetrahedra that share corners with two equivalent In(1)Se4 tetrahedra, corners with two equivalent In(2)Se4 tetrahedra, and corners with four equivalent Cu(1)Se4 tetrahedra. In the fourth In site, In(4) is bonded to two equivalent Se(1) and two equivalent Se(3) atoms to form InSe4 tetrahedra that share corners with two equivalent In(1)Se4 tetrahedra, corners with two equivalent In(2)Se4 tetrahedra, and corners with four equivalent Cu(1)Se4 tetrahedra. There are six inequivalent Se sites. In the first Se site, Se(5) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Cu(1), one In(2), and one In(3) atom. In the second Se site, Se(3) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Cu(1), one In(2), and one In(4) atom. In the third Se site, Se(6) is bonded in a rectangular see-saw-like geometry to one K(1), one K(2), one In(1), and one In(2) atom. In the fourth Se site, Se(1) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Cu(1), one In(1), and one In(4) atom. In the fifth Se site, Se(2) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Cu(1), one In(1), and one In(3) atom. In the sixth Se site, Se(4) is bonded in a rectangular see-saw-like geometry to one K(1), one K(2), one In(1), and one In(2) atom. is represented by the CIF card [CIF]
data_K2In3CuSe6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.250
_cell_length_b   8.250
_cell_length_c   21.723
_cell_angle_alpha   84.600
_cell_angle_beta   84.600
_cell_angle_gamma   90.019
_symmetry_Int_Tables_number   1
_cell_volume   1465.322
_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  0.762  0.395  0.417  1.0
  K  K1  1  0.605  0.238  0.083  1.0
  K  K2  1  0.238  0.605  0.583  1.0
  K  K3  1  0.395  0.762  0.917  1.0
  K  K4  1  0.780  0.896  0.417  1.0
  K  K5  1  0.104  0.220  0.083  1.0
  K  K6  1  0.220  0.104  0.583  1.0
  K  K7  1  0.896  0.780  0.917  1.0
  In  In8  1  0.279  0.154  0.385  1.0
  In  In9  1  0.846  0.721  0.115  1.0
  In  In10  1  0.721  0.846  0.615  1.0
  In  In11  1  0.154  0.279  0.885  1.0
  In  In12  1  0.346  0.722  0.115  1.0
  In  In13  1  0.278  0.654  0.385  1.0
  In  In14  1  0.654  0.278  0.885  1.0
  In  In15  1  0.722  0.346  0.615  1.0
  In  In16  1  0.561  0.439  0.250  1.0
  In  In17  1  0.439  0.561  0.750  1.0
  In  In18  1  0.063  0.937  0.250  1.0
  In  In19  1  0.937  0.063  0.750  1.0
  Cu  Cu20  1  0.063  0.438  0.250  1.0
  Cu  Cu21  1  0.562  0.937  0.250  1.0
  Cu  Cu22  1  0.937  0.562  0.750  1.0
  Cu  Cu23  1  0.438  0.063  0.750  1.0
  Se  Se24  1  0.183  0.027  0.820  1.0
  Se  Se25  1  0.973  0.817  0.680  1.0
  Se  Se26  1  0.817  0.973  0.180  1.0
  Se  Se27  1  0.027  0.183  0.320  1.0
  Se  Se28  1  0.158  0.564  0.820  1.0
  Se  Se29  1  0.436  0.842  0.680  1.0
  Se  Se30  1  0.842  0.436  0.180  1.0
  Se  Se31  1  0.564  0.158  0.320  1.0
  Se  Se32  1  0.974  0.343  0.681  1.0
  Se  Se33  1  0.657  0.026  0.819  1.0
  Se  Se34  1  0.026  0.657  0.319  1.0
  Se  Se35  1  0.343  0.974  0.181  1.0
  Se  Se36  1  0.885  0.266  0.960  1.0
  Se  Se37  1  0.734  0.115  0.540  1.0
  Se  Se38  1  0.115  0.734  0.040  1.0
  Se  Se39  1  0.266  0.885  0.460  1.0
  Se  Se40  1  0.436  0.316  0.681  1.0
  Se  Se41  1  0.684  0.564  0.819  1.0
  Se  Se42  1  0.564  0.684  0.319  1.0
  Se  Se43  1  0.316  0.436  0.181  1.0
  Se  Se44  1  0.386  0.254  0.960  1.0
  Se  Se45  1  0.746  0.614  0.540  1.0
  Se  Se46  1  0.614  0.746  0.040  1.0
  Se  Se47  1  0.254  0.386  0.460  1.0
[/CIF]
.