The structure described by Ta3CrSe6 is Ilmenite-like structured and crystallizes in the hexagonal P6_322 space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to six equivalent Se(1) atoms to form distorted TaSe6 pentagonal pyramids that share corners with six equivalent Cr(1)Se6 octahedra and edges with six equivalent Ta(2)Se6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 46°. In the second Ta site, Ta(2) is bonded to six equivalent Se(1) atoms to form distorted TaSe6 pentagonal pyramids that share corners with three equivalent Cr(1)Se6 octahedra, edges with three equivalent Ta(1)Se6 pentagonal pyramids, edges with three equivalent Ta(2)Se6 pentagonal pyramids, and  a faceface with one Cr(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 46°. Cr(1) is bonded to six equivalent Se(1) atoms to form CrSe6 octahedra that share corners with six equivalent Ta(1)Se6 pentagonal pyramids, corners with six equivalent Ta(2)Se6 pentagonal pyramids, and faces with two equivalent Ta(2)Se6 pentagonal pyramids. Se(1) is bonded to one Ta(1), two equivalent Ta(2), and one Cr(1) atom to form a mixture of edge, corner, and face-sharing SeTa3Cr trigonal pyramids. is represented by the CIF card [CIF]
data_Ta3CrSe6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.010
_cell_length_b   6.010
_cell_length_c   12.955
_cell_angle_alpha   90.001
_cell_angle_beta   89.999
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   405.268
_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
  Ta  Ta0  1  1.000  0.000  1.000  1.0
  Ta  Ta1  1  0.667  0.333  0.000  1.0
  Ta  Ta2  1  0.333  0.667  0.500  1.0
  Ta  Ta3  1  1.000  1.000  0.500  1.0
  Ta  Ta4  1  0.333  0.667  1.000  1.0
  Ta  Ta5  1  0.667  0.333  0.500  1.0
  Cr  Cr6  1  0.667  0.333  0.750  1.0
  Cr  Cr7  1  0.333  0.667  0.250  1.0
  Se  Se8  1  0.671  0.667  0.129  1.0
  Se  Se9  1  0.329  0.333  0.629  1.0
  Se  Se10  1  0.667  0.671  0.871  1.0
  Se  Se11  1  0.329  0.995  0.871  1.0
  Se  Se12  1  0.005  0.671  0.629  1.0
  Se  Se13  1  0.005  0.333  0.871  1.0
  Se  Se14  1  0.995  0.667  0.371  1.0
  Se  Se15  1  0.333  0.329  0.371  1.0
  Se  Se16  1  0.671  0.005  0.371  1.0
  Se  Se17  1  0.995  0.329  0.129  1.0
  Se  Se18  1  0.667  0.995  0.629  1.0
  Se  Se19  1  0.333  0.005  0.129  1.0
[/CIF]
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The structure described by Ta3CrSe6 is Ilmenite-like structured and crystallizes in the hexagonal P6_322 space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to six equivalent Se(1) atoms to form distorted TaSe6 pentagonal pyramids that share corners with six equivalent Cr(1)Se6 octahedra and edges with six equivalent Ta(2)Se6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 46°. In the second Ta site, Ta(2) is bonded to six equivalent Se(1) atoms to form distorted TaSe6 pentagonal pyramids that share corners with three equivalent Cr(1)Se6 octahedra, edges with three equivalent Ta(1)Se6 pentagonal pyramids, edges with three equivalent Ta(2)Se6 pentagonal pyramids, and  a faceface with one Cr(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 46°. Cr(1) is bonded to six equivalent Se(1) atoms to form CrSe6 octahedra that share corners with six equivalent Ta(1)Se6 pentagonal pyramids, corners with six equivalent Ta(2)Se6 pentagonal pyramids, and faces with two equivalent Ta(2)Se6 pentagonal pyramids. Se(1) is bonded to one Ta(1), two equivalent Ta(2), and one Cr(1) atom to form a mixture of edge, corner, and face-sharing SeTa3Cr trigonal pyramids. is represented by the CIF card [CIF]
data_Ta3CrSe6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.010
_cell_length_b   6.010
_cell_length_c   12.955
_cell_angle_alpha   90.001
_cell_angle_beta   89.999
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   405.268
_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
  Ta  Ta0  1  1.000  0.000  1.000  1.0
  Ta  Ta1  1  0.667  0.333  0.000  1.0
  Ta  Ta2  1  0.333  0.667  0.500  1.0
  Ta  Ta3  1  1.000  1.000  0.500  1.0
  Ta  Ta4  1  0.333  0.667  1.000  1.0
  Ta  Ta5  1  0.667  0.333  0.500  1.0
  Cr  Cr6  1  0.667  0.333  0.750  1.0
  Cr  Cr7  1  0.333  0.667  0.250  1.0
  Se  Se8  1  0.671  0.667  0.129  1.0
  Se  Se9  1  0.329  0.333  0.629  1.0
  Se  Se10  1  0.667  0.671  0.871  1.0
  Se  Se11  1  0.329  0.995  0.871  1.0
  Se  Se12  1  0.005  0.671  0.629  1.0
  Se  Se13  1  0.005  0.333  0.871  1.0
  Se  Se14  1  0.995  0.667  0.371  1.0
  Se  Se15  1  0.333  0.329  0.371  1.0
  Se  Se16  1  0.671  0.005  0.371  1.0
  Se  Se17  1  0.995  0.329  0.129  1.0
  Se  Se18  1  0.667  0.995  0.629  1.0
  Se  Se19  1  0.333  0.005  0.129  1.0
[/CIF]
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