The structure described by Ta3Co8Si crystallizes in the trigonal P3m1 space group. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 16-coordinate geometry to one Ta(2), three equivalent Co(1), three equivalent Co(3), six equivalent Co(4), and three equivalent Si(1) atoms. In the second Ta site, Ta(2) is bonded in a 12-coordinate geometry to one Ta(1), three equivalent Ta(3), three equivalent Co(2), three equivalent Co(3), and six equivalent Co(4) atoms. In the third Ta site, Ta(3) is bonded in a 16-coordinate geometry to three equivalent Ta(2), three equivalent Co(2), three equivalent Co(4), six equivalent Co(3), and one Si(1) atom. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to three equivalent Ta(1), three equivalent Co(3), three equivalent Co(4), and three equivalent Si(1) atoms to form CoTa3Co6Si3 cuboctahedra that share corners with six equivalent Co(3)Ta4Co6Si2 cuboctahedra, corners with six equivalent Co(4)Ta5Co6Si cuboctahedra, edges with six equivalent Co(1)Ta3Co6Si3 cuboctahedra, faces with two equivalent Co(2)Ta6Co6 cuboctahedra, faces with nine equivalent Co(3)Ta4Co6Si2 cuboctahedra, and faces with nine equivalent Co(4)Ta5Co6Si cuboctahedra. In the second Co site, Co(2) is bonded to three equivalent Ta(2), three equivalent Ta(3), three equivalent Co(3), and three equivalent Co(4) atoms to form CoTa6Co6 cuboctahedra that share corners with six equivalent Co(3)Ta4Co6Si2 cuboctahedra, corners with six equivalent Co(4)Ta5Co6Si cuboctahedra, edges with six equivalent Co(2)Ta6Co6 cuboctahedra, faces with two equivalent Co(1)Ta3Co6Si3 cuboctahedra, faces with nine equivalent Co(3)Ta4Co6Si2 cuboctahedra, and faces with nine equivalent Co(4)Ta5Co6Si cuboctahedra. In the third Co site, Co(3) is bonded to one Ta(1), one Ta(2), two equivalent Ta(3), one Co(1), one Co(2), four equivalent Co(3), and two equivalent Si(1) atoms to form distorted CoTa4Co6Si2 cuboctahedra that share corners with two equivalent Co(1)Ta3Co6Si3 cuboctahedra, corners with two equivalent Co(2)Ta6Co6 cuboctahedra, corners with four equivalent Co(3)Ta4Co6Si2 cuboctahedra, corners with ten equivalent Co(4)Ta5Co6Si cuboctahedra, edges with two equivalent Co(3)Ta4Co6Si2 cuboctahedra, edges with four equivalent Co(4)Ta5Co6Si cuboctahedra, faces with three equivalent Co(1)Ta3Co6Si3 cuboctahedra, faces with three equivalent Co(2)Ta6Co6 cuboctahedra, faces with four equivalent Co(4)Ta5Co6Si cuboctahedra, and faces with eight equivalent Co(3)Ta4Co6Si2 cuboctahedra. In the fourth Co site, Co(4) is bonded to one Ta(3), two equivalent Ta(1), two equivalent Ta(2), one Co(1), one Co(2), four equivalent Co(4), and one Si(1) atom to form CoTa5Co6Si cuboctahedra that share corners with two equivalent Co(1)Ta3Co6Si3 cuboctahedra, corners with two equivalent Co(2)Ta6Co6 cuboctahedra, corners with four equivalent Co(4)Ta5Co6Si cuboctahedra, corners with ten equivalent Co(3)Ta4Co6Si2 cuboctahedra, edges with two equivalent Co(4)Ta5Co6Si cuboctahedra, edges with four equivalent Co(3)Ta4Co6Si2 cuboctahedra, faces with three equivalent Co(1)Ta3Co6Si3 cuboctahedra, faces with three equivalent Co(2)Ta6Co6 cuboctahedra, faces with four equivalent Co(3)Ta4Co6Si2 cuboctahedra, and faces with eight equivalent Co(4)Ta5Co6Si cuboctahedra. Si(1) is bonded in a 16-coordinate geometry to one Ta(3), three equivalent Ta(1), three equivalent Co(1), three equivalent Co(4), and six equivalent Co(3) atoms. is represented by the CIF file [CIF]
data_Ta3Co8Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.742
_cell_length_b   4.742
_cell_length_c   7.679
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   149.535
_cell_formula_units_Z   1
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  0.667  0.333  0.555  1.0
  Ta  Ta1  1  0.667  0.333  0.928  1.0
  Ta  Ta2  1  0.000  0.000  0.090  1.0
  Co  Co3  1  0.333  0.667  0.495  1.0
  Co  Co4  1  0.333  0.667  0.994  1.0
  Co  Co5  1  0.997  0.499  0.248  1.0
  Co  Co6  1  0.501  0.499  0.248  1.0
  Co  Co7  1  0.501  0.003  0.248  1.0
  Co  Co8  1  0.671  0.836  0.746  1.0
  Co  Co9  1  0.164  0.836  0.746  1.0
  Co  Co10  1  0.164  0.329  0.746  1.0
  Si  Si11  1  0.000  0.000  0.456  1.0
[/CIF]
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The structure described by Ta3Co8Si crystallizes in the trigonal P3m1 space group. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 16-coordinate geometry to one Ta(2), three equivalent Co(1), three equivalent Co(3), six equivalent Co(4), and three equivalent Si(1) atoms. In the second Ta site, Ta(2) is bonded in a 12-coordinate geometry to one Ta(1), three equivalent Ta(3), three equivalent Co(2), three equivalent Co(3), and six equivalent Co(4) atoms. In the third Ta site, Ta(3) is bonded in a 16-coordinate geometry to three equivalent Ta(2), three equivalent Co(2), three equivalent Co(4), six equivalent Co(3), and one Si(1) atom. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to three equivalent Ta(1), three equivalent Co(3), three equivalent Co(4), and three equivalent Si(1) atoms to form CoTa3Co6Si3 cuboctahedra that share corners with six equivalent Co(3)Ta4Co6Si2 cuboctahedra, corners with six equivalent Co(4)Ta5Co6Si cuboctahedra, edges with six equivalent Co(1)Ta3Co6Si3 cuboctahedra, faces with two equivalent Co(2)Ta6Co6 cuboctahedra, faces with nine equivalent Co(3)Ta4Co6Si2 cuboctahedra, and faces with nine equivalent Co(4)Ta5Co6Si cuboctahedra. In the second Co site, Co(2) is bonded to three equivalent Ta(2), three equivalent Ta(3), three equivalent Co(3), and three equivalent Co(4) atoms to form CoTa6Co6 cuboctahedra that share corners with six equivalent Co(3)Ta4Co6Si2 cuboctahedra, corners with six equivalent Co(4)Ta5Co6Si cuboctahedra, edges with six equivalent Co(2)Ta6Co6 cuboctahedra, faces with two equivalent Co(1)Ta3Co6Si3 cuboctahedra, faces with nine equivalent Co(3)Ta4Co6Si2 cuboctahedra, and faces with nine equivalent Co(4)Ta5Co6Si cuboctahedra. In the third Co site, Co(3) is bonded to one Ta(1), one Ta(2), two equivalent Ta(3), one Co(1), one Co(2), four equivalent Co(3), and two equivalent Si(1) atoms to form distorted CoTa4Co6Si2 cuboctahedra that share corners with two equivalent Co(1)Ta3Co6Si3 cuboctahedra, corners with two equivalent Co(2)Ta6Co6 cuboctahedra, corners with four equivalent Co(3)Ta4Co6Si2 cuboctahedra, corners with ten equivalent Co(4)Ta5Co6Si cuboctahedra, edges with two equivalent Co(3)Ta4Co6Si2 cuboctahedra, edges with four equivalent Co(4)Ta5Co6Si cuboctahedra, faces with three equivalent Co(1)Ta3Co6Si3 cuboctahedra, faces with three equivalent Co(2)Ta6Co6 cuboctahedra, faces with four equivalent Co(4)Ta5Co6Si cuboctahedra, and faces with eight equivalent Co(3)Ta4Co6Si2 cuboctahedra. In the fourth Co site, Co(4) is bonded to one Ta(3), two equivalent Ta(1), two equivalent Ta(2), one Co(1), one Co(2), four equivalent Co(4), and one Si(1) atom to form CoTa5Co6Si cuboctahedra that share corners with two equivalent Co(1)Ta3Co6Si3 cuboctahedra, corners with two equivalent Co(2)Ta6Co6 cuboctahedra, corners with four equivalent Co(4)Ta5Co6Si cuboctahedra, corners with ten equivalent Co(3)Ta4Co6Si2 cuboctahedra, edges with two equivalent Co(4)Ta5Co6Si cuboctahedra, edges with four equivalent Co(3)Ta4Co6Si2 cuboctahedra, faces with three equivalent Co(1)Ta3Co6Si3 cuboctahedra, faces with three equivalent Co(2)Ta6Co6 cuboctahedra, faces with four equivalent Co(3)Ta4Co6Si2 cuboctahedra, and faces with eight equivalent Co(4)Ta5Co6Si cuboctahedra. Si(1) is bonded in a 16-coordinate geometry to one Ta(3), three equivalent Ta(1), three equivalent Co(1), three equivalent Co(4), and six equivalent Co(3) atoms. is represented by the CIF file [CIF]
data_Ta3Co8Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.742
_cell_length_b   4.742
_cell_length_c   7.679
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   149.535
_cell_formula_units_Z   1
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  0.667  0.333  0.555  1.0
  Ta  Ta1  1  0.667  0.333  0.928  1.0
  Ta  Ta2  1  0.000  0.000  0.090  1.0
  Co  Co3  1  0.333  0.667  0.495  1.0
  Co  Co4  1  0.333  0.667  0.994  1.0
  Co  Co5  1  0.997  0.499  0.248  1.0
  Co  Co6  1  0.501  0.499  0.248  1.0
  Co  Co7  1  0.501  0.003  0.248  1.0
  Co  Co8  1  0.671  0.836  0.746  1.0
  Co  Co9  1  0.164  0.836  0.746  1.0
  Co  Co10  1  0.164  0.329  0.746  1.0
  Si  Si11  1  0.000  0.000  0.456  1.0
[/CIF]
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