data_MgNbCl4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.8
_cell_length_b   5.8
_cell_length_c   5.8
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgNbCl4
_chemical_formula_sum   'Mg1 Nb1 Cl4'
_cell_volume   138.07
_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  Mg4  1  0.0  0.0  0.0  1.0
  Nb  Nb5  1  0.05  0.05  0.05  1.0
  Cl  Cl0  1  0.08  0.08  0.13  1.0
  Cl  Cl1  1  0.08  0.13  0.08  1.0
  Cl  Cl2  1  0.13  0.08  0.08  1.0
  Cl  Cl3  1  0.13  0.13  0.13  1.0

data_MgNbCl4
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.8
_cell_length_b   5.8
_cell_length_c   14.21
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   MgNbCl4
_chemical_formula_sum   'Mg3 Nb3 Cl12'
_cell_volume   414.2
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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  3  0.0  0.0  0.0  1.0
  Nb  Nb1  3  0.0  0.0  0.95  1.0
  Cl  Cl2  9  0.02  0.04  0.91  1.0
  Cl  Cl3  3  0.0  0.0  0.87  1.0

Mg Nb Cl Cl Cl Cl
Mg Nb Cl Cl Cl Cl 0 1 o o o 1 4 o o o 1 3 o o o 1 2 o o o 2 4 o o o 2 3 o o o 2 5 o o o 3 4 o o o 3 5 o o o 4 5 o o o 
MgNbCl4 is Copper structured and crystallizes in the trigonal R3m space group. The structure is zero-dimensional and consists of three MgNbCl4 clusters. Mg(1) is bonded in a single-bond geometry to one Nb(1) atom. The Mg(1)-Nb(1) bond length is 0.73 Å. Nb(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1) and three equivalent Cl(1) atoms. All Nb(1)-Cl(1) bond lengths are 0.63 Å. There are two inequivalent Cl sites. In the first Cl site, Cl(2) is bonded in a 3-coordinate geometry to three equivalent Cl(1) atoms. All Cl(2)-Cl(1) bond lengths are 0.54 Å. In the second Cl site, Cl(1) is bonded in a 3-coordinate geometry to one Nb(1), one Cl(2), and two equivalent Cl(1) atoms. Both Cl(1)-Cl(1) bond lengths are 0.31 Å.