The crystal structure described by Nb4AlN3 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 to three equivalent N(1) and three equivalent N(2) atoms to form a mixture of distorted corner and edge-sharing NbN6 pentagonal pyramids. In the second Nb site, Nb(2) is bonded in a 3-coordinate geometry to three equivalent Al(1) and three equivalent N(2) atoms. Al(1) is bonded to six equivalent Nb(2) and six equivalent Al(1) atoms to form AlNb6Al6 cuboctahedra that share corners with six equivalent Al(1)Nb6Al6 cuboctahedra, corners with six equivalent N(2)Nb6 octahedra, edges with six equivalent Al(1)Nb6Al6 cuboctahedra, edges with six equivalent N(2)Nb6 octahedra, and faces with six equivalent Al(1)Nb6Al6 cuboctahedra. The corner-sharing octahedral tilt angles are 13°. There are two inequivalent N sites. In the first N site, N(1) is bonded to six equivalent Nb(1) atoms to form a mixture of face, corner, and edge-sharing NNb6 octahedra. The corner-sharing octahedral tilt angles are 46°. In the second N site, N(2) is bonded to three equivalent Nb(1) and three equivalent Nb(2) atoms to form NNb6 octahedra that share corners with three equivalent Al(1)Nb6Al6 cuboctahedra, corners with six equivalent N(1)Nb6 octahedra, edges with three equivalent Al(1)Nb6Al6 cuboctahedra, edges with six equivalent N(2)Nb6 octahedra, and  a faceface with one N(1)Nb6 octahedra. The corner-sharing octahedral tilt angles are 46°. is represented by the CIF file [CIF]
data_Nb4AlN3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.006
_cell_length_b   3.006
_cell_length_c   25.667
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   200.892
_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  0.333  0.667  0.445  1.0
  Nb  Nb1  1  0.667  0.333  0.555  1.0
  Nb  Nb2  1  0.667  0.333  0.945  1.0
  Nb  Nb3  1  0.333  0.667  0.055  1.0
  Nb  Nb4  1  0.333  0.667  0.837  1.0
  Nb  Nb5  1  0.667  0.333  0.163  1.0
  Nb  Nb6  1  0.667  0.333  0.337  1.0
  Nb  Nb7  1  0.333  0.667  0.663  1.0
  Al  Al8  1  0.333  0.667  0.250  1.0
  Al  Al9  1  0.667  0.333  0.750  1.0
  N  N10  1  0.000  0.000  0.500  1.0
  N  N11  1  0.000  0.000  0.000  1.0
  N  N12  1  0.000  0.000  0.391  1.0
  N  N13  1  0.000  0.000  0.609  1.0
  N  N14  1  0.000  0.000  0.891  1.0
  N  N15  1  0.000  0.000  0.109  1.0
[/CIF]
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The crystal structure described by Nb4AlN3 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 to three equivalent N(1) and three equivalent N(2) atoms to form a mixture of distorted corner and edge-sharing NbN6 pentagonal pyramids. In the second Nb site, Nb(2) is bonded in a 3-coordinate geometry to three equivalent Al(1) and three equivalent N(2) atoms. Al(1) is bonded to six equivalent Nb(2) and six equivalent Al(1) atoms to form AlNb6Al6 cuboctahedra that share corners with six equivalent Al(1)Nb6Al6 cuboctahedra, corners with six equivalent N(2)Nb6 octahedra, edges with six equivalent Al(1)Nb6Al6 cuboctahedra, edges with six equivalent N(2)Nb6 octahedra, and faces with six equivalent Al(1)Nb6Al6 cuboctahedra. The corner-sharing octahedral tilt angles are 13°. There are two inequivalent N sites. In the first N site, N(1) is bonded to six equivalent Nb(1) atoms to form a mixture of face, corner, and edge-sharing NNb6 octahedra. The corner-sharing octahedral tilt angles are 46°. In the second N site, N(2) is bonded to three equivalent Nb(1) and three equivalent Nb(2) atoms to form NNb6 octahedra that share corners with three equivalent Al(1)Nb6Al6 cuboctahedra, corners with six equivalent N(1)Nb6 octahedra, edges with three equivalent Al(1)Nb6Al6 cuboctahedra, edges with six equivalent N(2)Nb6 octahedra, and  a faceface with one N(1)Nb6 octahedra. The corner-sharing octahedral tilt angles are 46°. is represented by the CIF file [CIF]
data_Nb4AlN3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.006
_cell_length_b   3.006
_cell_length_c   25.667
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   200.892
_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  0.333  0.667  0.445  1.0
  Nb  Nb1  1  0.667  0.333  0.555  1.0
  Nb  Nb2  1  0.667  0.333  0.945  1.0
  Nb  Nb3  1  0.333  0.667  0.055  1.0
  Nb  Nb4  1  0.333  0.667  0.837  1.0
  Nb  Nb5  1  0.667  0.333  0.163  1.0
  Nb  Nb6  1  0.667  0.333  0.337  1.0
  Nb  Nb7  1  0.333  0.667  0.663  1.0
  Al  Al8  1  0.333  0.667  0.250  1.0
  Al  Al9  1  0.667  0.333  0.750  1.0
  N  N10  1  0.000  0.000  0.500  1.0
  N  N11  1  0.000  0.000  0.000  1.0
  N  N12  1  0.000  0.000  0.391  1.0
  N  N13  1  0.000  0.000  0.609  1.0
  N  N14  1  0.000  0.000  0.891  1.0
  N  N15  1  0.000  0.000  0.109  1.0
[/CIF]
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