data_MgFe4Cu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.8
_cell_length_b   4.8
_cell_length_c   4.8
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgFe4Cu
_chemical_formula_sum   'Mg1 Fe4 Cu1'
_cell_volume   78.0
_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  Mg5  1  0.0  0.0  0.0  1.0
  Fe  Fe1  1  0.24  0.54  0.54  1.0
  Fe  Fe2  1  0.54  0.54  0.24  1.0
  Fe  Fe3  1  0.54  0.24  0.54  1.0
  Fe  Fe4  1  0.24  0.24  0.24  1.0
  Cu  Cu0  1  0.7  0.7  0.7  1.0

data_MgFe4Cu
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.8
_cell_length_b   4.8
_cell_length_c   11.75
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   MgFe4Cu
_chemical_formula_sum   'Mg3 Fe12 Cu3'
_cell_volume   234.0
_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
  Fe  Fe1  9  0.2  0.1  0.56  1.0
  Fe  Fe2  3  0.0  0.0  0.76  1.0
  Cu  Cu3  3  0.0  0.0  0.3  1.0

Mg Fe Fe Fe Fe Cu
Mg Fe Fe Fe Fe Cu 0 4 o - o 0 4 - o o 0 4 o o - 0 4 o o o 0 2 - - o 0 2 - o o 0 2 o - o 0 5 - - o 0 5 - o - 0 5 o - - 0 3 - o - 0 3 - o o 0 3 o o - 0 1 o - - 0 1 o - o 0 1 o o - 1 3 o o o 1 2 o o o 1 4 o + o 1 4 o o + 1 4 o o o 1 5 - o o 2 3 o o o 2 4 + o o 2 4 o + o 2 4 o o o 2 5 o o - 3 4 + o o 3 4 o o + 3 4 o o o 3 5 o - o 4 5 - o o 4 5 o - o 4 5 o o - 
MgFe4Cu crystallizes in the trigonal R3m space group. Mg(1) is bonded in a 16-coordinate geometry to four equivalent Fe(2), nine equivalent Fe(1), and three equivalent Cu(1) atoms. There is one shorter (2.81 Å) and three longer (2.98 Å) Mg(1)-Fe(2) bond lengths. There are six shorter (2.77 Å) and three longer (3.27 Å) Mg(1)-Fe(1) bond lengths. All Mg(1)-Cu(1) bond lengths are 2.79 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 3-coordinate geometry to three equivalent Mg(1), two equivalent Fe(1), three equivalent Fe(2), and one Cu(1) atom. Both Fe(1)-Fe(1) bond lengths are 1.46 Å. There is one shorter (2.53 Å) and two longer (2.90 Å) Fe(1)-Fe(2) bond lengths. The Fe(1)-Cu(1) bond length is 2.14 Å. In the second Fe site, Fe(2) is bonded in a 16-coordinate geometry to four equivalent Mg(1), nine equivalent Fe(1), and three equivalent Cu(1) atoms. All Fe(2)-Cu(1) bond lengths are 3.12 Å. Cu(1) is bonded in a 6-coordinate geometry to three equivalent Mg(1), three equivalent Fe(1), and three equivalent Fe(2) atoms.