The crystal structure described by TaCr4Si crystallizes in the trigonal P-3m1 space group. Ta(1) is bonded in a 16-coordinate geometry to three equivalent Ta(1), three equivalent Cr(2), nine equivalent Cr(3), and one Si(1) atom. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to six equivalent Cr(3) and six equivalent Si(1) atoms to form CrCr6Si6 cuboctahedra that share corners with twelve equivalent Cr(3)Ta3Cr6Si3 cuboctahedra, edges with six equivalent Cr(1)Cr6Si6 cuboctahedra, faces with two equivalent Cr(2)Ta6Cr6 cuboctahedra, and faces with eighteen equivalent Cr(3)Ta3Cr6Si3 cuboctahedra. In the second Cr site, Cr(2) is bonded to six equivalent Ta(1) and six equivalent Cr(3) atoms to form CrTa6Cr6 cuboctahedra that share corners with twelve equivalent Cr(3)Ta3Cr6Si3 cuboctahedra, edges with six equivalent Cr(2)Ta6Cr6 cuboctahedra, faces with two equivalent Cr(1)Cr6Si6 cuboctahedra, and faces with eighteen equivalent Cr(3)Ta3Cr6Si3 cuboctahedra. In the third Cr site, Cr(3) is bonded to three equivalent Ta(1), one Cr(1), one Cr(2), four equivalent Cr(3), and three equivalent Si(1) atoms to form CrTa3Cr6Si3 cuboctahedra that share corners with two equivalent Cr(1)Cr6Si6 cuboctahedra, corners with two equivalent Cr(2)Ta6Cr6 cuboctahedra, corners with fourteen equivalent Cr(3)Ta3Cr6Si3 cuboctahedra, edges with six equivalent Cr(3)Ta3Cr6Si3 cuboctahedra, faces with three equivalent Cr(1)Cr6Si6 cuboctahedra, faces with three equivalent Cr(2)Ta6Cr6 cuboctahedra, and faces with twelve equivalent Cr(3)Ta3Cr6Si3 cuboctahedra. Si(1) is bonded in a 13-coordinate geometry to one Ta(1), three equivalent Cr(1), and nine equivalent Cr(3) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_TaCr4Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.868
_cell_length_b   4.868
_cell_length_c   7.641
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   156.826
_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  0.667  0.333  0.934  1.0
  Ta  Ta1  1  0.333  0.667  0.066  1.0
  Cr  Cr2  1  0.000  0.000  0.500  1.0
  Cr  Cr3  1  0.000  0.000  0.000  1.0
  Cr  Cr4  1  0.828  0.172  0.262  1.0
  Cr  Cr5  1  0.828  0.656  0.262  1.0
  Cr  Cr6  1  0.344  0.172  0.262  1.0
  Cr  Cr7  1  0.172  0.828  0.738  1.0
  Cr  Cr8  1  0.172  0.344  0.738  1.0
  Cr  Cr9  1  0.656  0.828  0.738  1.0
  Si  Si10  1  0.333  0.667  0.432  1.0
  Si  Si11  1  0.667  0.333  0.568  1.0
[/CIF]
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The crystal structure described by TaCr4Si crystallizes in the trigonal P-3m1 space group. Ta(1) is bonded in a 16-coordinate geometry to three equivalent Ta(1), three equivalent Cr(2), nine equivalent Cr(3), and one Si(1) atom. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to six equivalent Cr(3) and six equivalent Si(1) atoms to form CrCr6Si6 cuboctahedra that share corners with twelve equivalent Cr(3)Ta3Cr6Si3 cuboctahedra, edges with six equivalent Cr(1)Cr6Si6 cuboctahedra, faces with two equivalent Cr(2)Ta6Cr6 cuboctahedra, and faces with eighteen equivalent Cr(3)Ta3Cr6Si3 cuboctahedra. In the second Cr site, Cr(2) is bonded to six equivalent Ta(1) and six equivalent Cr(3) atoms to form CrTa6Cr6 cuboctahedra that share corners with twelve equivalent Cr(3)Ta3Cr6Si3 cuboctahedra, edges with six equivalent Cr(2)Ta6Cr6 cuboctahedra, faces with two equivalent Cr(1)Cr6Si6 cuboctahedra, and faces with eighteen equivalent Cr(3)Ta3Cr6Si3 cuboctahedra. In the third Cr site, Cr(3) is bonded to three equivalent Ta(1), one Cr(1), one Cr(2), four equivalent Cr(3), and three equivalent Si(1) atoms to form CrTa3Cr6Si3 cuboctahedra that share corners with two equivalent Cr(1)Cr6Si6 cuboctahedra, corners with two equivalent Cr(2)Ta6Cr6 cuboctahedra, corners with fourteen equivalent Cr(3)Ta3Cr6Si3 cuboctahedra, edges with six equivalent Cr(3)Ta3Cr6Si3 cuboctahedra, faces with three equivalent Cr(1)Cr6Si6 cuboctahedra, faces with three equivalent Cr(2)Ta6Cr6 cuboctahedra, and faces with twelve equivalent Cr(3)Ta3Cr6Si3 cuboctahedra. Si(1) is bonded in a 13-coordinate geometry to one Ta(1), three equivalent Cr(1), and nine equivalent Cr(3) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_TaCr4Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.868
_cell_length_b   4.868
_cell_length_c   7.641
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   156.826
_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  0.667  0.333  0.934  1.0
  Ta  Ta1  1  0.333  0.667  0.066  1.0
  Cr  Cr2  1  0.000  0.000  0.500  1.0
  Cr  Cr3  1  0.000  0.000  0.000  1.0
  Cr  Cr4  1  0.828  0.172  0.262  1.0
  Cr  Cr5  1  0.828  0.656  0.262  1.0
  Cr  Cr6  1  0.344  0.172  0.262  1.0
  Cr  Cr7  1  0.172  0.828  0.738  1.0
  Cr  Cr8  1  0.172  0.344  0.738  1.0
  Cr  Cr9  1  0.656  0.828  0.738  1.0
  Si  Si10  1  0.333  0.667  0.432  1.0
  Si  Si11  1  0.667  0.333  0.568  1.0
[/CIF]
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