The crystal structure described by Ta4AlC3 is MAX Phase structured and crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 3-coordinate geometry to three equivalent Al(1) and three equivalent C(1) atoms. In the second Ta site, Ta(2) is bonded to three equivalent C(1) and three equivalent C(2) atoms to form a mixture of edge and corner-sharing TaC6 octahedra. The corner-sharing octahedra are not tilted. Al(1) is bonded in a 6-coordinate geometry to six equivalent Ta(1) atoms. There are two inequivalent C sites. In the first C site, C(1) is bonded to three equivalent Ta(1) and three equivalent Ta(2) atoms to form a mixture of edge and corner-sharing CTa6 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second C site, C(2) is bonded to six equivalent Ta(2) atoms to form a mixture of edge and corner-sharing CTa6 octahedra. The corner-sharing octahedral tilt angles are 1°. is represented by the CIF card [CIF]
data_Ta4AlC3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.129
_cell_length_b   3.129
_cell_length_c   24.147
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   204.796
_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  0.000  0.000  0.342  1.0
  Ta  Ta1  1  0.000  0.000  0.842  1.0
  Ta  Ta2  1  0.000  0.000  0.658  1.0
  Ta  Ta3  1  0.000  0.000  0.158  1.0
  Ta  Ta4  1  0.333  0.667  0.445  1.0
  Ta  Ta5  1  0.667  0.333  0.945  1.0
  Ta  Ta6  1  0.667  0.333  0.555  1.0
  Ta  Ta7  1  0.333  0.667  0.055  1.0
  Al  Al8  1  0.667  0.333  0.750  1.0
  Al  Al9  1  0.333  0.667  0.250  1.0
  C  C10  1  0.667  0.333  0.392  1.0
  C  C11  1  0.333  0.667  0.892  1.0
  C  C12  1  0.333  0.667  0.608  1.0
  C  C13  1  0.000  0.000  0.000  1.0
  C  C14  1  0.667  0.333  0.108  1.0
  C  C15  1  0.000  0.000  0.500  1.0
[/CIF]
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The crystal structure described by Ta4AlC3 is MAX Phase structured and crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 3-coordinate geometry to three equivalent Al(1) and three equivalent C(1) atoms. In the second Ta site, Ta(2) is bonded to three equivalent C(1) and three equivalent C(2) atoms to form a mixture of edge and corner-sharing TaC6 octahedra. The corner-sharing octahedra are not tilted. Al(1) is bonded in a 6-coordinate geometry to six equivalent Ta(1) atoms. There are two inequivalent C sites. In the first C site, C(1) is bonded to three equivalent Ta(1) and three equivalent Ta(2) atoms to form a mixture of edge and corner-sharing CTa6 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second C site, C(2) is bonded to six equivalent Ta(2) atoms to form a mixture of edge and corner-sharing CTa6 octahedra. The corner-sharing octahedral tilt angles are 1°. is represented by the CIF card [CIF]
data_Ta4AlC3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.129
_cell_length_b   3.129
_cell_length_c   24.147
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   204.796
_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  0.000  0.000  0.342  1.0
  Ta  Ta1  1  0.000  0.000  0.842  1.0
  Ta  Ta2  1  0.000  0.000  0.658  1.0
  Ta  Ta3  1  0.000  0.000  0.158  1.0
  Ta  Ta4  1  0.333  0.667  0.445  1.0
  Ta  Ta5  1  0.667  0.333  0.945  1.0
  Ta  Ta6  1  0.667  0.333  0.555  1.0
  Ta  Ta7  1  0.333  0.667  0.055  1.0
  Al  Al8  1  0.667  0.333  0.750  1.0
  Al  Al9  1  0.333  0.667  0.250  1.0
  C  C10  1  0.667  0.333  0.392  1.0
  C  C11  1  0.333  0.667  0.892  1.0
  C  C12  1  0.333  0.667  0.608  1.0
  C  C13  1  0.000  0.000  0.000  1.0
  C  C14  1  0.667  0.333  0.108  1.0
  C  C15  1  0.000  0.000  0.500  1.0
[/CIF]
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