The material structure described by K3Ta2Ag3Se8 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(3), two equivalent Se(1), and three equivalent Se(4) atoms. In the second K site, K(2) is bonded in a 8-coordinate geometry to two equivalent Se(3), two equivalent Se(4), and four equivalent Se(2) atoms. Ta(1) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form TaSe4 tetrahedra that share edges with two equivalent Ag(2)Se4 tetrahedra. There are two inequivalent Ag sites. In the first Ag site, Ag(1) is bonded in a 4-coordinate geometry to two equivalent Se(2) and two equivalent Se(3) atoms. In the second Ag site, Ag(2) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form distorted AgSe4 tetrahedra that share edges with two equivalent Ta(1)Se4 tetrahedra. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a 4-coordinate geometry to two equivalent K(1), one Ta(1), and one Ag(2) atom. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to two equivalent K(2), one Ta(1), one Ag(1), and one Ag(2) atom. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Ta(1), one Ag(1), and one Ag(2) atom. In the fourth Se site, Se(4) is bonded in a 6-coordinate geometry to one K(2), three equivalent K(1), one Ta(1), and one Ag(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_K3Ta2Ag3Se8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   13.236
_cell_length_b   13.236
_cell_length_c   14.765
_cell_angle_alpha   61.517
_cell_angle_beta   61.517
_cell_angle_gamma   26.975
_symmetry_Int_Tables_number   1
_cell_volume   1022.498
_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
  K  K0  1  0.227  0.381  0.607  1.0
  K  K1  1  0.773  0.619  0.393  1.0
  K  K2  1  0.381  0.227  0.107  1.0
  K  K3  1  0.000  0.000  0.500  1.0
  K  K4  1  0.619  0.773  0.893  1.0
  K  K5  1  0.000  0.000  0.000  1.0
  Ta  Ta6  1  0.177  0.566  0.281  1.0
  Ta  Ta7  1  0.566  0.177  0.781  1.0
  Ta  Ta8  1  0.434  0.823  0.219  1.0
  Ta  Ta9  1  0.823  0.434  0.719  1.0
  Ag  Ag10  1  0.308  0.692  0.250  1.0
  Ag  Ag11  1  0.065  0.677  0.791  1.0
  Ag  Ag12  1  0.692  0.308  0.750  1.0
  Ag  Ag13  1  0.677  0.065  0.291  1.0
  Ag  Ag14  1  0.323  0.935  0.709  1.0
  Ag  Ag15  1  0.935  0.323  0.209  1.0
  Se  Se16  1  0.732  0.696  0.103  1.0
  Se  Se17  1  0.576  0.518  0.349  1.0
  Se  Se18  1  0.194  0.002  0.110  1.0
  Se  Se19  1  0.424  0.482  0.651  1.0
  Se  Se20  1  0.002  0.194  0.610  1.0
  Se  Se21  1  0.082  0.236  0.818  1.0
  Se  Se22  1  0.696  0.732  0.603  1.0
  Se  Se23  1  0.482  0.424  0.151  1.0
  Se  Se24  1  0.518  0.576  0.849  1.0
  Se  Se25  1  0.304  0.268  0.397  1.0
  Se  Se26  1  0.764  0.918  0.682  1.0
  Se  Se27  1  0.806  0.998  0.890  1.0
  Se  Se28  1  0.268  0.304  0.897  1.0
  Se  Se29  1  0.998  0.806  0.390  1.0
  Se  Se30  1  0.918  0.764  0.182  1.0
  Se  Se31  1  0.236  0.082  0.318  1.0
[/CIF]
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The material structure described by K3Ta2Ag3Se8 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(3), two equivalent Se(1), and three equivalent Se(4) atoms. In the second K site, K(2) is bonded in a 8-coordinate geometry to two equivalent Se(3), two equivalent Se(4), and four equivalent Se(2) atoms. Ta(1) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form TaSe4 tetrahedra that share edges with two equivalent Ag(2)Se4 tetrahedra. There are two inequivalent Ag sites. In the first Ag site, Ag(1) is bonded in a 4-coordinate geometry to two equivalent Se(2) and two equivalent Se(3) atoms. In the second Ag site, Ag(2) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form distorted AgSe4 tetrahedra that share edges with two equivalent Ta(1)Se4 tetrahedra. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a 4-coordinate geometry to two equivalent K(1), one Ta(1), and one Ag(2) atom. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to two equivalent K(2), one Ta(1), one Ag(1), and one Ag(2) atom. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Ta(1), one Ag(1), and one Ag(2) atom. In the fourth Se site, Se(4) is bonded in a 6-coordinate geometry to one K(2), three equivalent K(1), one Ta(1), and one Ag(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_K3Ta2Ag3Se8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   13.236
_cell_length_b   13.236
_cell_length_c   14.765
_cell_angle_alpha   61.517
_cell_angle_beta   61.517
_cell_angle_gamma   26.975
_symmetry_Int_Tables_number   1
_cell_volume   1022.498
_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
  K  K0  1  0.227  0.381  0.607  1.0
  K  K1  1  0.773  0.619  0.393  1.0
  K  K2  1  0.381  0.227  0.107  1.0
  K  K3  1  0.000  0.000  0.500  1.0
  K  K4  1  0.619  0.773  0.893  1.0
  K  K5  1  0.000  0.000  0.000  1.0
  Ta  Ta6  1  0.177  0.566  0.281  1.0
  Ta  Ta7  1  0.566  0.177  0.781  1.0
  Ta  Ta8  1  0.434  0.823  0.219  1.0
  Ta  Ta9  1  0.823  0.434  0.719  1.0
  Ag  Ag10  1  0.308  0.692  0.250  1.0
  Ag  Ag11  1  0.065  0.677  0.791  1.0
  Ag  Ag12  1  0.692  0.308  0.750  1.0
  Ag  Ag13  1  0.677  0.065  0.291  1.0
  Ag  Ag14  1  0.323  0.935  0.709  1.0
  Ag  Ag15  1  0.935  0.323  0.209  1.0
  Se  Se16  1  0.732  0.696  0.103  1.0
  Se  Se17  1  0.576  0.518  0.349  1.0
  Se  Se18  1  0.194  0.002  0.110  1.0
  Se  Se19  1  0.424  0.482  0.651  1.0
  Se  Se20  1  0.002  0.194  0.610  1.0
  Se  Se21  1  0.082  0.236  0.818  1.0
  Se  Se22  1  0.696  0.732  0.603  1.0
  Se  Se23  1  0.482  0.424  0.151  1.0
  Se  Se24  1  0.518  0.576  0.849  1.0
  Se  Se25  1  0.304  0.268  0.397  1.0
  Se  Se26  1  0.764  0.918  0.682  1.0
  Se  Se27  1  0.806  0.998  0.890  1.0
  Se  Se28  1  0.268  0.304  0.897  1.0
  Se  Se29  1  0.998  0.806  0.390  1.0
  Se  Se30  1  0.918  0.764  0.182  1.0
  Se  Se31  1  0.236  0.082  0.318  1.0
[/CIF]
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