data_HfMgCr4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.97
_cell_length_b   4.97
_cell_length_c   4.97
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   HfMgCr4
_chemical_formula_sum   'Hf1 Mg1 Cr4'
_cell_volume   86.58
_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
  Hf  Hf4  1  0.27  0.27  0.27  1.0
  Mg  Mg5  1  0.0  0.0  0.0  1.0
  Cr  Cr0  1  0.39  0.39  0.63  1.0
  Cr  Cr1  1  0.39  0.63  0.39  1.0
  Cr  Cr2  1  0.63  0.39  0.39  1.0
  Cr  Cr3  1  0.63  0.63  0.63  1.0

data_HfMgCr4
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.97
_cell_length_b   4.97
_cell_length_c   12.16
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   HfMgCr4
_chemical_formula_sum   'Hf3 Mg3 Cr12'
_cell_volume   259.75
_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
  Hf  Hf0  3  0.0  0.0  0.73  1.0
  Mg  Mg1  3  0.0  0.0  0.0  1.0
  Cr  Cr2  9  0.08  0.16  0.53  1.0
  Cr  Cr3  3  0.0  0.0  0.37  1.0

Hf Mg Cr Cr Cr Cr
MgHfCr4 crystallizes in the trigonal R3m space group. Mg(1) is bonded in a 6-coordinate geometry to three equivalent Cr(1) and three equivalent Cr(2) atoms. All Mg(1)-Cr(1) bond lengths are 2.77 Å. All Mg(1)-Cr(2) bond lengths are 2.90 Å. Hf(1) is bonded in a 9-coordinate geometry to three equivalent Cr(2) and six equivalent Cr(1) atoms. All Hf(1)-Cr(2) bond lengths are 2.89 Å. There are three shorter (2.58 Å) and three longer (2.69 Å) Hf(1)-Cr(1) bond lengths. There are two inequivalent Cr sites. In the first Cr site, Cr(2) is bonded in a 9-coordinate geometry to three equivalent Mg(1), three equivalent Hf(1), and three equivalent Cr(1) atoms. All Cr(2)-Cr(1) bond lengths are 2.03 Å. In the second Cr site, Cr(1) is bonded in a 6-coordinate geometry to one Mg(1), two equivalent Hf(1), one Cr(2), and two equivalent Cr(1) atoms. Both Cr(1)-Cr(1) bond lengths are 1.17 Å.