The compound described by Cs3Tm2I9 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 9-coordinate geometry to nine equivalent I(2) atoms. In the second Cs site, Cs(2) is bonded to six equivalent I(1) and six equivalent I(2) atoms to form CsI12 cuboctahedra that share corners with six equivalent Cs(2)I12 cuboctahedra and faces with six equivalent Tm(1)I6 octahedra. Tm(1) is bonded to three equivalent I(1) and three equivalent I(2) atoms to form TmI6 octahedra that share faces with three equivalent Cs(2)I12 cuboctahedra and  a faceface with one Tm(1)I6 octahedra. There are two inequivalent I sites. In the first I site, I(1) is bonded in a 2-coordinate geometry to two equivalent Cs(2) and two equivalent Tm(1) atoms. In the second I site, I(2) is bonded in a distorted single-bond geometry to one Cs(2), three equivalent Cs(1), and one Tm(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cs3Tm2I9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.472
_cell_length_b   8.472
_cell_length_c   21.367
_cell_angle_alpha   89.986
_cell_angle_beta   90.014
_cell_angle_gamma   119.995
_symmetry_Int_Tables_number   1
_cell_volume   1328.082
_cell_formula_units_Z   2
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  0.667  0.333  0.568  1.0
  Cs  Cs1  1  1.000  0.000  0.250  1.0
  Cs  Cs2  1  0.333  0.667  0.068  1.0
  Cs  Cs3  1  0.333  0.667  0.432  1.0
  Cs  Cs4  1  1.000  0.000  0.750  1.0
  Cs  Cs5  1  0.667  0.333  0.931  1.0
  Tm  Tm6  1  0.667  0.333  0.344  1.0
  Tm  Tm7  1  0.333  0.667  0.844  1.0
  Tm  Tm8  1  0.333  0.667  0.656  1.0
  Tm  Tm9  1  0.667  0.333  0.156  1.0
  I  I10  1  0.506  0.494  0.250  1.0
  I  I11  1  0.835  0.670  0.086  1.0
  I  I12  1  0.330  0.165  0.414  1.0
  I  I13  1  0.165  0.835  0.914  1.0
  I  I14  1  0.165  0.330  0.586  1.0
  I  I15  1  0.330  0.165  0.086  1.0
  I  I16  1  0.165  0.835  0.586  1.0
  I  I17  1  0.670  0.835  0.586  1.0
  I  I18  1  0.989  0.494  0.250  1.0
  I  I19  1  0.011  0.506  0.750  1.0
  I  I20  1  0.506  0.011  0.250  1.0
  I  I21  1  0.670  0.835  0.914  1.0
  I  I22  1  0.835  0.165  0.086  1.0
  I  I23  1  0.494  0.989  0.750  1.0
  I  I24  1  0.835  0.165  0.414  1.0
  I  I25  1  0.165  0.330  0.914  1.0
  I  I26  1  0.835  0.670  0.414  1.0
  I  I27  1  0.494  0.506  0.750  1.0
[/CIF]
.
The compound described by Cs3Tm2I9 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 9-coordinate geometry to nine equivalent I(2) atoms. In the second Cs site, Cs(2) is bonded to six equivalent I(1) and six equivalent I(2) atoms to form CsI12 cuboctahedra that share corners with six equivalent Cs(2)I12 cuboctahedra and faces with six equivalent Tm(1)I6 octahedra. Tm(1) is bonded to three equivalent I(1) and three equivalent I(2) atoms to form TmI6 octahedra that share faces with three equivalent Cs(2)I12 cuboctahedra and  a faceface with one Tm(1)I6 octahedra. There are two inequivalent I sites. In the first I site, I(1) is bonded in a 2-coordinate geometry to two equivalent Cs(2) and two equivalent Tm(1) atoms. In the second I site, I(2) is bonded in a distorted single-bond geometry to one Cs(2), three equivalent Cs(1), and one Tm(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cs3Tm2I9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.472
_cell_length_b   8.472
_cell_length_c   21.367
_cell_angle_alpha   89.986
_cell_angle_beta   90.014
_cell_angle_gamma   119.995
_symmetry_Int_Tables_number   1
_cell_volume   1328.082
_cell_formula_units_Z   2
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  0.667  0.333  0.568  1.0
  Cs  Cs1  1  1.000  0.000  0.250  1.0
  Cs  Cs2  1  0.333  0.667  0.068  1.0
  Cs  Cs3  1  0.333  0.667  0.432  1.0
  Cs  Cs4  1  1.000  0.000  0.750  1.0
  Cs  Cs5  1  0.667  0.333  0.931  1.0
  Tm  Tm6  1  0.667  0.333  0.344  1.0
  Tm  Tm7  1  0.333  0.667  0.844  1.0
  Tm  Tm8  1  0.333  0.667  0.656  1.0
  Tm  Tm9  1  0.667  0.333  0.156  1.0
  I  I10  1  0.506  0.494  0.250  1.0
  I  I11  1  0.835  0.670  0.086  1.0
  I  I12  1  0.330  0.165  0.414  1.0
  I  I13  1  0.165  0.835  0.914  1.0
  I  I14  1  0.165  0.330  0.586  1.0
  I  I15  1  0.330  0.165  0.086  1.0
  I  I16  1  0.165  0.835  0.586  1.0
  I  I17  1  0.670  0.835  0.586  1.0
  I  I18  1  0.989  0.494  0.250  1.0
  I  I19  1  0.011  0.506  0.750  1.0
  I  I20  1  0.506  0.011  0.250  1.0
  I  I21  1  0.670  0.835  0.914  1.0
  I  I22  1  0.835  0.165  0.086  1.0
  I  I23  1  0.494  0.989  0.750  1.0
  I  I24  1  0.835  0.165  0.414  1.0
  I  I25  1  0.165  0.330  0.914  1.0
  I  I26  1  0.835  0.670  0.414  1.0
  I  I27  1  0.494  0.506  0.750  1.0
[/CIF]
.