The structure described by NbCuAl crystallizes in the orthorhombic Amm2 space group. There are five inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 16-coordinate geometry to one Nb(1); three Nb(2,2); one Cu(3); two equivalent Cu(1); two equivalent Cu(2); three equivalent Al(1); and four equivalent Al(2) atoms. In the second Nb site, Nb(2) is bonded in a 16-coordinate geometry to one Nb(2); three Nb(1,1); one Cu(1); two equivalent Cu(3); four equivalent Cu(2); two equivalent Al(2); and three equivalent Al(1) atoms. In the third Nb site, Nb(1) is bonded in a 16-coordinate geometry to one Nb(1), three equivalent Nb(2), one Cu(3), two equivalent Cu(1), two equivalent Cu(2), three equivalent Al(1), and four equivalent Al(2) atoms. In the fourth Nb site, Nb(1) is bonded in a 16-coordinate geometry to one Nb(1); three Nb(2,2); one Cu(3); two equivalent Cu(1); two equivalent Cu(2); three equivalent Al(1); and four equivalent Al(2) atoms. In the fifth Nb site, Nb(2) is bonded in a 16-coordinate geometry to one Nb(2); three Nb(1,1); one Cu(1); two equivalent Cu(3); four equivalent Cu(2); two equivalent Al(2); and three equivalent Al(1) atoms. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent Nb(2); four Nb(1,1); two equivalent Al(1); and four equivalent Al(2) atoms to form distorted CuNb6Al6 cuboctahedra that share corners with two equivalent Cu(3)Nb6Al2Cu4 cuboctahedra, corners with four equivalent Cu(1)Nb6Al6 cuboctahedra, corners with eight equivalent Cu(2)Nb6Al2Cu4 cuboctahedra, edges with two equivalent Cu(1)Nb6Al6 cuboctahedra, edges with four equivalent Cu(3)Nb6Al2Cu4 cuboctahedra, and faces with four equivalent Cu(2)Nb6Al2Cu4 cuboctahedra. In the second Cu site, Cu(2) is bonded to two Nb(1,1); four Nb(2,2); two equivalent Cu(2); two equivalent Cu(3); and two equivalent Al(1) atoms to form distorted CuNb6Al2Cu4 cuboctahedra that share corners with four equivalent Cu(2)Nb6Al2Cu4 cuboctahedra, corners with four equivalent Cu(1)Nb6Al6 cuboctahedra, edges with two equivalent Cu(2)Nb6Al2Cu4 cuboctahedra, faces with two equivalent Cu(1)Nb6Al6 cuboctahedra, faces with four equivalent Cu(2)Nb6Al2Cu4 cuboctahedra, and faces with four equivalent Cu(3)Nb6Al2Cu4 cuboctahedra. In the third Cu site, Cu(3) is bonded to two Nb(1,1); four Nb(2,2); four equivalent Cu(2); and two equivalent Al(1) atoms to form distorted CuNb6Al2Cu4 cuboctahedra that share corners with two equivalent Cu(1)Nb6Al6 cuboctahedra, corners with four equivalent Cu(3)Nb6Al2Cu4 cuboctahedra, edges with two equivalent Cu(3)Nb6Al2Cu4 cuboctahedra, edges with four equivalent Cu(1)Nb6Al6 cuboctahedra, and faces with eight equivalent Cu(2)Nb6Al2Cu4 cuboctahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 4-coordinate geometry to three Nb(1,1); three Nb(2,2); one Cu(1); one Cu(3); two equivalent Cu(2); and two equivalent Al(2) atoms. In the second Al site, Al(2) is bonded in a 12-coordinate geometry to two equivalent Nb(2); four Nb(1,1,1); two equivalent Cu(1); two equivalent Al(1); and two equivalent Al(2) atoms. is represented by the CIF file [CIF]
data_NbAlCu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.975
_cell_length_b   5.066
_cell_length_c   8.079
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.607
_symmetry_Int_Tables_number   1
_cell_volume   175.249
_cell_formula_units_Z   4
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  0.672  0.336  0.562  1.0
  Nb  Nb1  1  0.324  0.662  0.433  1.0
  Nb  Nb2  1  0.324  0.662  0.067  1.0
  Nb  Nb3  1  0.672  0.336  0.938  1.0
  Al  Al4  1  0.988  0.994  0.487  1.0
  Al  Al5  1  0.988  0.994  0.013  1.0
  Al  Al6  1  0.187  0.352  0.750  1.0
  Al  Al7  1  0.187  0.836  0.750  1.0
  Cu  Cu8  1  0.677  0.839  0.750  1.0
  Cu  Cu9  1  0.820  0.650  0.250  1.0
  Cu  Cu10  1  0.820  0.170  0.250  1.0
  Cu  Cu11  1  0.339  0.170  0.250  1.0
[/CIF]
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The structure described by NbCuAl crystallizes in the orthorhombic Amm2 space group. There are five inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 16-coordinate geometry to one Nb(1); three Nb(2,2); one Cu(3); two equivalent Cu(1); two equivalent Cu(2); three equivalent Al(1); and four equivalent Al(2) atoms. In the second Nb site, Nb(2) is bonded in a 16-coordinate geometry to one Nb(2); three Nb(1,1); one Cu(1); two equivalent Cu(3); four equivalent Cu(2); two equivalent Al(2); and three equivalent Al(1) atoms. In the third Nb site, Nb(1) is bonded in a 16-coordinate geometry to one Nb(1), three equivalent Nb(2), one Cu(3), two equivalent Cu(1), two equivalent Cu(2), three equivalent Al(1), and four equivalent Al(2) atoms. In the fourth Nb site, Nb(1) is bonded in a 16-coordinate geometry to one Nb(1); three Nb(2,2); one Cu(3); two equivalent Cu(1); two equivalent Cu(2); three equivalent Al(1); and four equivalent Al(2) atoms. In the fifth Nb site, Nb(2) is bonded in a 16-coordinate geometry to one Nb(2); three Nb(1,1); one Cu(1); two equivalent Cu(3); four equivalent Cu(2); two equivalent Al(2); and three equivalent Al(1) atoms. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent Nb(2); four Nb(1,1); two equivalent Al(1); and four equivalent Al(2) atoms to form distorted CuNb6Al6 cuboctahedra that share corners with two equivalent Cu(3)Nb6Al2Cu4 cuboctahedra, corners with four equivalent Cu(1)Nb6Al6 cuboctahedra, corners with eight equivalent Cu(2)Nb6Al2Cu4 cuboctahedra, edges with two equivalent Cu(1)Nb6Al6 cuboctahedra, edges with four equivalent Cu(3)Nb6Al2Cu4 cuboctahedra, and faces with four equivalent Cu(2)Nb6Al2Cu4 cuboctahedra. In the second Cu site, Cu(2) is bonded to two Nb(1,1); four Nb(2,2); two equivalent Cu(2); two equivalent Cu(3); and two equivalent Al(1) atoms to form distorted CuNb6Al2Cu4 cuboctahedra that share corners with four equivalent Cu(2)Nb6Al2Cu4 cuboctahedra, corners with four equivalent Cu(1)Nb6Al6 cuboctahedra, edges with two equivalent Cu(2)Nb6Al2Cu4 cuboctahedra, faces with two equivalent Cu(1)Nb6Al6 cuboctahedra, faces with four equivalent Cu(2)Nb6Al2Cu4 cuboctahedra, and faces with four equivalent Cu(3)Nb6Al2Cu4 cuboctahedra. In the third Cu site, Cu(3) is bonded to two Nb(1,1); four Nb(2,2); four equivalent Cu(2); and two equivalent Al(1) atoms to form distorted CuNb6Al2Cu4 cuboctahedra that share corners with two equivalent Cu(1)Nb6Al6 cuboctahedra, corners with four equivalent Cu(3)Nb6Al2Cu4 cuboctahedra, edges with two equivalent Cu(3)Nb6Al2Cu4 cuboctahedra, edges with four equivalent Cu(1)Nb6Al6 cuboctahedra, and faces with eight equivalent Cu(2)Nb6Al2Cu4 cuboctahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 4-coordinate geometry to three Nb(1,1); three Nb(2,2); one Cu(1); one Cu(3); two equivalent Cu(2); and two equivalent Al(2) atoms. In the second Al site, Al(2) is bonded in a 12-coordinate geometry to two equivalent Nb(2); four Nb(1,1,1); two equivalent Cu(1); two equivalent Al(1); and two equivalent Al(2) atoms. is represented by the CIF file [CIF]
data_NbAlCu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.975
_cell_length_b   5.066
_cell_length_c   8.079
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.607
_symmetry_Int_Tables_number   1
_cell_volume   175.249
_cell_formula_units_Z   4
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  0.672  0.336  0.562  1.0
  Nb  Nb1  1  0.324  0.662  0.433  1.0
  Nb  Nb2  1  0.324  0.662  0.067  1.0
  Nb  Nb3  1  0.672  0.336  0.938  1.0
  Al  Al4  1  0.988  0.994  0.487  1.0
  Al  Al5  1  0.988  0.994  0.013  1.0
  Al  Al6  1  0.187  0.352  0.750  1.0
  Al  Al7  1  0.187  0.836  0.750  1.0
  Cu  Cu8  1  0.677  0.839  0.750  1.0
  Cu  Cu9  1  0.820  0.650  0.250  1.0
  Cu  Cu10  1  0.820  0.170  0.250  1.0
  Cu  Cu11  1  0.339  0.170  0.250  1.0
[/CIF]
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