The structure described by MgNb3 is alpha bismuth trifluoride structured and crystallizes in the tetragonal I4/mmm space group. Mg(1) is bonded to four equivalent Nb(1) and eight equivalent Nb(2) atoms to form distorted MgNb12 cuboctahedra that share corners with four equivalent Mg(1)Nb12 cuboctahedra, corners with eight equivalent Nb(1)Mg4Nb8 cuboctahedra, edges with eight equivalent Mg(1)Nb12 cuboctahedra, faces with four equivalent Mg(1)Nb12 cuboctahedra, and faces with six equivalent Nb(1)Mg4Nb8 cuboctahedra. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to four equivalent Mg(1) and eight equivalent Nb(2) atoms to form NbMg4Nb8 cuboctahedra that share corners with four equivalent Nb(1)Mg4Nb8 cuboctahedra, corners with eight equivalent Mg(1)Nb12 cuboctahedra, edges with eight equivalent Nb(1)Mg4Nb8 cuboctahedra, faces with four equivalent Nb(1)Mg4Nb8 cuboctahedra, and faces with six equivalent Mg(1)Nb12 cuboctahedra. In the second Nb site, Nb(2) is bonded in a 4-coordinate geometry to four equivalent Mg(1) and four equivalent Nb(1) atoms. is represented by the CIF file [CIF]
data_MgNb3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.859
_cell_length_b   4.859
_cell_length_c   4.859
_cell_angle_alpha   125.334
_cell_angle_beta   125.334
_cell_angle_gamma   80.985
_symmetry_Int_Tables_number   1
_cell_volume   73.568
_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
  Mg  Mg0  1  0.000  0.000  0.000  1.0
  Nb  Nb1  1  0.500  0.500  0.000  1.0
  Nb  Nb2  1  0.750  0.250  0.500  1.0
  Nb  Nb3  1  0.250  0.750  0.500  1.0
[/CIF]
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The structure described by MgNb3 is alpha bismuth trifluoride structured and crystallizes in the tetragonal I4/mmm space group. Mg(1) is bonded to four equivalent Nb(1) and eight equivalent Nb(2) atoms to form distorted MgNb12 cuboctahedra that share corners with four equivalent Mg(1)Nb12 cuboctahedra, corners with eight equivalent Nb(1)Mg4Nb8 cuboctahedra, edges with eight equivalent Mg(1)Nb12 cuboctahedra, faces with four equivalent Mg(1)Nb12 cuboctahedra, and faces with six equivalent Nb(1)Mg4Nb8 cuboctahedra. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to four equivalent Mg(1) and eight equivalent Nb(2) atoms to form NbMg4Nb8 cuboctahedra that share corners with four equivalent Nb(1)Mg4Nb8 cuboctahedra, corners with eight equivalent Mg(1)Nb12 cuboctahedra, edges with eight equivalent Nb(1)Mg4Nb8 cuboctahedra, faces with four equivalent Nb(1)Mg4Nb8 cuboctahedra, and faces with six equivalent Mg(1)Nb12 cuboctahedra. In the second Nb site, Nb(2) is bonded in a 4-coordinate geometry to four equivalent Mg(1) and four equivalent Nb(1) atoms. is represented by the CIF file [CIF]
data_MgNb3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.859
_cell_length_b   4.859
_cell_length_c   4.859
_cell_angle_alpha   125.334
_cell_angle_beta   125.334
_cell_angle_gamma   80.985
_symmetry_Int_Tables_number   1
_cell_volume   73.568
_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
  Mg  Mg0  1  0.000  0.000  0.000  1.0
  Nb  Nb1  1  0.500  0.500  0.000  1.0
  Nb  Nb2  1  0.750  0.250  0.500  1.0
  Nb  Nb3  1  0.250  0.750  0.500  1.0
[/CIF]
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