The material structure described by Nb3AlC2 is MAX Phase-like structured and crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 3-coordinate geometry to three equivalent Al(1) and three equivalent C(1) atoms. In the second Nb site, Nb(2) is bonded to six equivalent C(1) atoms to form edge-sharing NbC6 octahedra. Al(1) is bonded to six equivalent Nb(1) atoms to form distorted AlNb6 cuboctahedra that share corners with six equivalent C(1)Nb6 octahedra, edges with six equivalent Al(1)Nb6 cuboctahedra, and edges with six equivalent C(1)Nb6 octahedra. The corner-sharing octahedral tilt angles are 17°. C(1) is bonded to three equivalent Nb(1) and three equivalent Nb(2) atoms to form CNb6 octahedra that share corners with three equivalent Al(1)Nb6 cuboctahedra, corners with three equivalent C(1)Nb6 octahedra, edges with three equivalent Al(1)Nb6 cuboctahedra, and edges with nine equivalent C(1)Nb6 octahedra. The corner-sharing octahedra are not tilted. is represented by the CIF card [CIF]
data_Nb3AlC2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.133
_cell_length_b   3.133
_cell_length_c   19.202
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   163.258
_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
  Nb  Nb0  1  0.667  0.333  0.366  1.0
  Nb  Nb1  1  0.333  0.667  0.866  1.0
  Nb  Nb2  1  0.333  0.667  0.634  1.0
  Nb  Nb3  1  0.667  0.333  0.134  1.0
  Nb  Nb4  1  0.000  0.000  0.500  1.0
  Nb  Nb5  1  0.000  0.000  0.000  1.0
  Al  Al6  1  0.000  0.000  0.750  1.0
  Al  Al7  1  0.000  0.000  0.250  1.0
  C  C8  1  0.333  0.667  0.431  1.0
  C  C9  1  0.667  0.333  0.931  1.0
  C  C10  1  0.333  0.667  0.069  1.0
  C  C11  1  0.667  0.333  0.569  1.0
[/CIF]
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The material structure described by Nb3AlC2 is MAX Phase-like structured and crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 3-coordinate geometry to three equivalent Al(1) and three equivalent C(1) atoms. In the second Nb site, Nb(2) is bonded to six equivalent C(1) atoms to form edge-sharing NbC6 octahedra. Al(1) is bonded to six equivalent Nb(1) atoms to form distorted AlNb6 cuboctahedra that share corners with six equivalent C(1)Nb6 octahedra, edges with six equivalent Al(1)Nb6 cuboctahedra, and edges with six equivalent C(1)Nb6 octahedra. The corner-sharing octahedral tilt angles are 17°. C(1) is bonded to three equivalent Nb(1) and three equivalent Nb(2) atoms to form CNb6 octahedra that share corners with three equivalent Al(1)Nb6 cuboctahedra, corners with three equivalent C(1)Nb6 octahedra, edges with three equivalent Al(1)Nb6 cuboctahedra, and edges with nine equivalent C(1)Nb6 octahedra. The corner-sharing octahedra are not tilted. is represented by the CIF card [CIF]
data_Nb3AlC2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.133
_cell_length_b   3.133
_cell_length_c   19.202
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   163.258
_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
  Nb  Nb0  1  0.667  0.333  0.366  1.0
  Nb  Nb1  1  0.333  0.667  0.866  1.0
  Nb  Nb2  1  0.333  0.667  0.634  1.0
  Nb  Nb3  1  0.667  0.333  0.134  1.0
  Nb  Nb4  1  0.000  0.000  0.500  1.0
  Nb  Nb5  1  0.000  0.000  0.000  1.0
  Al  Al6  1  0.000  0.000  0.750  1.0
  Al  Al7  1  0.000  0.000  0.250  1.0
  C  C8  1  0.333  0.667  0.431  1.0
  C  C9  1  0.667  0.333  0.931  1.0
  C  C10  1  0.333  0.667  0.069  1.0
  C  C11  1  0.667  0.333  0.569  1.0
[/CIF]
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