The material structure described by Nb3Cr8Al is Hexagonal Laves-derived structured and crystallizes in the trigonal P3m1 space group. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 16-coordinate geometry to one Nb(2), three equivalent Cr(1), three equivalent Cr(3), six equivalent Cr(4), and three equivalent Al(1) atoms. In the second Nb site, Nb(2) is bonded in a 16-coordinate geometry to one Nb(1), three equivalent Nb(3), three equivalent Cr(2), three equivalent Cr(3), and six equivalent Cr(4) atoms. In the third Nb site, Nb(3) is bonded in a 16-coordinate geometry to three equivalent Nb(2), three equivalent Cr(2), three equivalent Cr(4), six equivalent Cr(3), and one Al(1) atom. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to three equivalent Nb(1), three equivalent Cr(3), three equivalent Cr(4), and three equivalent Al(1) atoms to form CrNb3Al3Cr6 cuboctahedra that share corners with six equivalent Cr(3)Nb4Al2Cr6 cuboctahedra, corners with six equivalent Cr(4)Nb5AlCr6 cuboctahedra, edges with six equivalent Cr(1)Nb3Al3Cr6 cuboctahedra, faces with two equivalent Cr(2)Nb6Cr6 cuboctahedra, faces with nine equivalent Cr(3)Nb4Al2Cr6 cuboctahedra, and faces with nine equivalent Cr(4)Nb5AlCr6 cuboctahedra. In the second Cr site, Cr(2) is bonded to three equivalent Nb(2), three equivalent Nb(3), three equivalent Cr(3), and three equivalent Cr(4) atoms to form CrNb6Cr6 cuboctahedra that share corners with six equivalent Cr(3)Nb4Al2Cr6 cuboctahedra, corners with six equivalent Cr(4)Nb5AlCr6 cuboctahedra, edges with six equivalent Cr(2)Nb6Cr6 cuboctahedra, faces with two equivalent Cr(1)Nb3Al3Cr6 cuboctahedra, faces with nine equivalent Cr(3)Nb4Al2Cr6 cuboctahedra, and faces with nine equivalent Cr(4)Nb5AlCr6 cuboctahedra. In the third Cr site, Cr(3) is bonded to one Nb(1), one Nb(2), two equivalent Nb(3), one Cr(1), one Cr(2), four equivalent Cr(3), and two equivalent Al(1) atoms to form CrNb4Al2Cr6 cuboctahedra that share corners with two equivalent Cr(1)Nb3Al3Cr6 cuboctahedra, corners with two equivalent Cr(2)Nb6Cr6 cuboctahedra, corners with four equivalent Cr(3)Nb4Al2Cr6 cuboctahedra, corners with ten equivalent Cr(4)Nb5AlCr6 cuboctahedra, edges with two equivalent Cr(3)Nb4Al2Cr6 cuboctahedra, edges with four equivalent Cr(4)Nb5AlCr6 cuboctahedra, faces with three equivalent Cr(1)Nb3Al3Cr6 cuboctahedra, faces with three equivalent Cr(2)Nb6Cr6 cuboctahedra, faces with four equivalent Cr(4)Nb5AlCr6 cuboctahedra, and faces with eight equivalent Cr(3)Nb4Al2Cr6 cuboctahedra. In the fourth Cr site, Cr(4) is bonded to one Nb(3), two equivalent Nb(1), two equivalent Nb(2), one Cr(1), one Cr(2), four equivalent Cr(4), and one Al(1) atom to form CrNb5AlCr6 cuboctahedra that share corners with two equivalent Cr(1)Nb3Al3Cr6 cuboctahedra, corners with two equivalent Cr(2)Nb6Cr6 cuboctahedra, corners with four equivalent Cr(4)Nb5AlCr6 cuboctahedra, corners with ten equivalent Cr(3)Nb4Al2Cr6 cuboctahedra, edges with two equivalent Cr(4)Nb5AlCr6 cuboctahedra, edges with four equivalent Cr(3)Nb4Al2Cr6 cuboctahedra, faces with three equivalent Cr(1)Nb3Al3Cr6 cuboctahedra, faces with three equivalent Cr(2)Nb6Cr6 cuboctahedra, faces with four equivalent Cr(3)Nb4Al2Cr6 cuboctahedra, and faces with eight equivalent Cr(4)Nb5AlCr6 cuboctahedra. Al(1) is bonded in a 16-coordinate geometry to one Nb(3), three equivalent Nb(1), three equivalent Cr(1), three equivalent Cr(4), and six equivalent Cr(3) atoms. is represented by the CIF card [CIF]
data_Nb3AlCr8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.873
_cell_length_b   4.873
_cell_length_c   8.004
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   164.625
_cell_formula_units_Z   1
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  0.443  1.0
  Nb  Nb1  1  0.667  0.333  0.060  1.0
  Nb  Nb2  1  0.000  0.000  0.936  1.0
  Al  Al3  1  0.000  0.000  0.563  1.0
  Cr  Cr4  1  0.333  0.667  0.499  1.0
  Cr  Cr5  1  0.333  0.667  0.999  1.0
  Cr  Cr6  1  0.502  0.004  0.748  1.0
  Cr  Cr7  1  0.502  0.498  0.748  1.0
  Cr  Cr8  1  0.996  0.498  0.748  1.0
  Cr  Cr9  1  0.163  0.326  0.252  1.0
  Cr  Cr10  1  0.163  0.837  0.252  1.0
  Cr  Cr11  1  0.674  0.837  0.252  1.0
[/CIF]
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The material structure described by Nb3Cr8Al is Hexagonal Laves-derived structured and crystallizes in the trigonal P3m1 space group. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 16-coordinate geometry to one Nb(2), three equivalent Cr(1), three equivalent Cr(3), six equivalent Cr(4), and three equivalent Al(1) atoms. In the second Nb site, Nb(2) is bonded in a 16-coordinate geometry to one Nb(1), three equivalent Nb(3), three equivalent Cr(2), three equivalent Cr(3), and six equivalent Cr(4) atoms. In the third Nb site, Nb(3) is bonded in a 16-coordinate geometry to three equivalent Nb(2), three equivalent Cr(2), three equivalent Cr(4), six equivalent Cr(3), and one Al(1) atom. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to three equivalent Nb(1), three equivalent Cr(3), three equivalent Cr(4), and three equivalent Al(1) atoms to form CrNb3Al3Cr6 cuboctahedra that share corners with six equivalent Cr(3)Nb4Al2Cr6 cuboctahedra, corners with six equivalent Cr(4)Nb5AlCr6 cuboctahedra, edges with six equivalent Cr(1)Nb3Al3Cr6 cuboctahedra, faces with two equivalent Cr(2)Nb6Cr6 cuboctahedra, faces with nine equivalent Cr(3)Nb4Al2Cr6 cuboctahedra, and faces with nine equivalent Cr(4)Nb5AlCr6 cuboctahedra. In the second Cr site, Cr(2) is bonded to three equivalent Nb(2), three equivalent Nb(3), three equivalent Cr(3), and three equivalent Cr(4) atoms to form CrNb6Cr6 cuboctahedra that share corners with six equivalent Cr(3)Nb4Al2Cr6 cuboctahedra, corners with six equivalent Cr(4)Nb5AlCr6 cuboctahedra, edges with six equivalent Cr(2)Nb6Cr6 cuboctahedra, faces with two equivalent Cr(1)Nb3Al3Cr6 cuboctahedra, faces with nine equivalent Cr(3)Nb4Al2Cr6 cuboctahedra, and faces with nine equivalent Cr(4)Nb5AlCr6 cuboctahedra. In the third Cr site, Cr(3) is bonded to one Nb(1), one Nb(2), two equivalent Nb(3), one Cr(1), one Cr(2), four equivalent Cr(3), and two equivalent Al(1) atoms to form CrNb4Al2Cr6 cuboctahedra that share corners with two equivalent Cr(1)Nb3Al3Cr6 cuboctahedra, corners with two equivalent Cr(2)Nb6Cr6 cuboctahedra, corners with four equivalent Cr(3)Nb4Al2Cr6 cuboctahedra, corners with ten equivalent Cr(4)Nb5AlCr6 cuboctahedra, edges with two equivalent Cr(3)Nb4Al2Cr6 cuboctahedra, edges with four equivalent Cr(4)Nb5AlCr6 cuboctahedra, faces with three equivalent Cr(1)Nb3Al3Cr6 cuboctahedra, faces with three equivalent Cr(2)Nb6Cr6 cuboctahedra, faces with four equivalent Cr(4)Nb5AlCr6 cuboctahedra, and faces with eight equivalent Cr(3)Nb4Al2Cr6 cuboctahedra. In the fourth Cr site, Cr(4) is bonded to one Nb(3), two equivalent Nb(1), two equivalent Nb(2), one Cr(1), one Cr(2), four equivalent Cr(4), and one Al(1) atom to form CrNb5AlCr6 cuboctahedra that share corners with two equivalent Cr(1)Nb3Al3Cr6 cuboctahedra, corners with two equivalent Cr(2)Nb6Cr6 cuboctahedra, corners with four equivalent Cr(4)Nb5AlCr6 cuboctahedra, corners with ten equivalent Cr(3)Nb4Al2Cr6 cuboctahedra, edges with two equivalent Cr(4)Nb5AlCr6 cuboctahedra, edges with four equivalent Cr(3)Nb4Al2Cr6 cuboctahedra, faces with three equivalent Cr(1)Nb3Al3Cr6 cuboctahedra, faces with three equivalent Cr(2)Nb6Cr6 cuboctahedra, faces with four equivalent Cr(3)Nb4Al2Cr6 cuboctahedra, and faces with eight equivalent Cr(4)Nb5AlCr6 cuboctahedra. Al(1) is bonded in a 16-coordinate geometry to one Nb(3), three equivalent Nb(1), three equivalent Cr(1), three equivalent Cr(4), and six equivalent Cr(3) atoms. is represented by the CIF card [CIF]
data_Nb3AlCr8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.873
_cell_length_b   4.873
_cell_length_c   8.004
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   164.625
_cell_formula_units_Z   1
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  0.443  1.0
  Nb  Nb1  1  0.667  0.333  0.060  1.0
  Nb  Nb2  1  0.000  0.000  0.936  1.0
  Al  Al3  1  0.000  0.000  0.563  1.0
  Cr  Cr4  1  0.333  0.667  0.499  1.0
  Cr  Cr5  1  0.333  0.667  0.999  1.0
  Cr  Cr6  1  0.502  0.004  0.748  1.0
  Cr  Cr7  1  0.502  0.498  0.748  1.0
  Cr  Cr8  1  0.996  0.498  0.748  1.0
  Cr  Cr9  1  0.163  0.326  0.252  1.0
  Cr  Cr10  1  0.163  0.837  0.252  1.0
  Cr  Cr11  1  0.674  0.837  0.252  1.0
[/CIF]
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