data_Cs2TbMg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.77
_cell_length_b   6.77
_cell_length_c   6.77
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Cs2TbMg
_chemical_formula_sum   'Cs2 Tb1 Mg1'
_cell_volume   218.95
_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
  Cs  Cs0  1  0.39  0.39  0.39  1.0
  Cs  Cs1  1  0.18  0.18  0.18  1.0
  Tb  Tb3  1  0.78  0.78  0.78  1.0
  Mg  Mg2  1  0.0  0.0  0.0  1.0

data_Cs2TbMg
_symmetry_space_group_name_H-M   R3m
_cell_length_a   6.77
_cell_length_b   6.77
_cell_length_c   16.57
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Cs2TbMg
_chemical_formula_sum   'Cs6 Tb3 Mg3'
_cell_volume   656.85
_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
  Cs  Cs0  3  0.0  0.0  0.61  1.0
  Cs  Cs1  3  0.0  0.0  0.82  1.0
  Tb  Tb2  3  0.0  0.0  0.22  1.0
  Mg  Mg3  3  0.0  0.0  0.0  1.0

Cs Cs Tb Mg
Cs Cs Tb Mg 0 1 o o o 0 1 o o + 0 1 + o o 0 1 o + o 0 3 o o + 0 3 o + o 0 3 + o o 0 2 - o o 0 2 o - o 0 2 o o - 1 3 o o o 1 2 o - - 1 2 - o - 1 2 - - o 2 3 + o + 2 3 o + + 2 3 + + o 2 3 + + + 
Cs2MgTb crystallizes in the trigonal R3m space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 7-coordinate geometry to one Cs(2), three equivalent Mg(1), and three equivalent Tb(1) atoms. The Cs(1)-Cs(2) bond length is 3.58 Å. All Cs(1)-Mg(1) bond lengths are 4.02 Å. All Cs(1)-Tb(1) bond lengths are 4.02 Å. In the second Cs site, Cs(2) is bonded in a distorted single-bond geometry to one Cs(1), one Mg(1), and three equivalent Tb(1) atoms. The Cs(2)-Mg(1) bond length is 2.91 Å. All Cs(2)-Tb(1) bond lengths are 4.02 Å. Mg(1) is bonded in a 5-coordinate geometry to one Cs(2), three equivalent Cs(1), and one Tb(1) atom. The Mg(1)-Tb(1) bond length is 3.58 Å. Tb(1) is bonded to three equivalent Cs(1), three equivalent Cs(2), and one Mg(1) atom to form distorted edge-sharing TbCs6Mg hexagonal pyramids.