data_MgTlCu4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.04
_cell_length_b   5.04
_cell_length_c   5.04
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgTlCu4
_chemical_formula_sum   'Mg1 Tl1 Cu4'
_cell_volume   90.27
_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
  Tl  Tl5  1  0.34  0.34  0.34  1.0
  Cu  Cu0  1  0.46  0.67  0.46  1.0
  Cu  Cu1  1  0.67  0.46  0.46  1.0
  Cu  Cu2  1  0.67  0.67  0.67  1.0
  Cu  Cu3  1  0.46  0.46  0.67  1.0

data_MgTlCu4
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.04
_cell_length_b   5.04
_cell_length_c   12.33
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   MgTlCu4
_chemical_formula_sum   'Mg3 Tl3 Cu12'
_cell_volume   270.82
_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
  Tl  Tl1  3  0.0  0.0  0.66  1.0
  Cu  Cu2  9  0.07  0.14  0.47  1.0
  Cu  Cu3  3  0.0  0.0  0.33  1.0

Mg Tl Cu Cu Cu Cu
MgCu4Tl crystallizes in the trigonal R3m space group. Mg(1) is bonded in a 15-coordinate geometry to three equivalent Cu(2), nine equivalent Cu(1), and three equivalent Tl(1) atoms. All Mg(1)-Cu(2) bond lengths are 2.91 Å. There are six shorter (3.18 Å) and three longer (3.30 Å) Mg(1)-Cu(1) bond lengths. All Mg(1)-Tl(1) bond lengths are 2.91 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(2) is bonded in a distorted q6 geometry to three equivalent Mg(1), three equivalent Cu(1), and three equivalent Tl(1) atoms. All Cu(2)-Cu(1) bond lengths are 1.83 Å. All Cu(2)-Tl(1) bond lengths are 2.91 Å. In the second Cu site, Cu(1) is bonded in a 2-coordinate geometry to three equivalent Mg(1), one Cu(2), two equivalent Cu(1), and two equivalent Tl(1) atoms. Both Cu(1)-Cu(1) bond lengths are 1.06 Å. There is one shorter (2.36 Å) and one longer (2.94 Å) Cu(1)-Tl(1) bond length. Tl(1) is bonded to three equivalent Mg(1), three equivalent Cu(2), and six equivalent Cu(1) atoms to form a mixture of corner and edge-sharing TlMg3Cu9 cuboctahedra.