The crystal structure described by Er7CoI12 is trigonal omega-derived structured and crystallizes in the trigonal R-3 space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to six equivalent I(1) atoms to form edge-sharing ErI6 octahedra. In the second Er site, Er(2) is bonded to one Co(1), two equivalent I(1), and three equivalent I(2) atoms to form distorted ErCoI5 octahedra that share corners with three equivalent Er(2)CoI5 octahedra,  an edgeedge with one Er(1)I6 octahedra, and edges with five equivalent Er(2)CoI5 octahedra. The corner-sharing octahedral tilt angles range from 0-10°. Co(1) is bonded in an octahedral geometry to six equivalent Er(2) atoms. There are two inequivalent I sites. In the first I site, I(1) is bonded in a distorted T-shaped geometry to one Er(1) and two equivalent Er(2) atoms. In the second I site, I(2) is bonded in a 3-coordinate geometry to three equivalent Er(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Er7CoI12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.585
_cell_length_b   9.585
_cell_length_c   9.585
_cell_angle_alpha   106.862
_cell_angle_beta   106.862
_cell_angle_gamma   106.862
_symmetry_Int_Tables_number   1
_cell_volume   736.014
_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
  Er  Er0  1  0.500  0.500  0.500  1.0
  Er  Er1  1  0.286  0.091  0.022  1.0
  Er  Er2  1  0.022  0.286  0.091  1.0
  Er  Er3  1  0.091  0.022  0.286  1.0
  Er  Er4  1  0.714  0.909  0.978  1.0
  Er  Er5  1  0.978  0.714  0.909  1.0
  Er  Er6  1  0.909  0.978  0.714  1.0
  Co  Co7  1  0.000  0.000  0.000  1.0
  I  I8  1  0.466  0.160  0.388  1.0
  I  I9  1  0.388  0.466  0.160  1.0
  I  I10  1  0.160  0.388  0.466  1.0
  I  I11  1  0.534  0.840  0.612  1.0
  I  I12  1  0.612  0.534  0.840  1.0
  I  I13  1  0.840  0.612  0.534  1.0
  I  I14  1  0.324  0.774  0.929  1.0
  I  I15  1  0.929  0.324  0.774  1.0
  I  I16  1  0.774  0.929  0.324  1.0
  I  I17  1  0.676  0.226  0.071  1.0
  I  I18  1  0.071  0.676  0.226  1.0
  I  I19  1  0.226  0.071  0.676  1.0
[/CIF]
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The crystal structure described by Er7CoI12 is trigonal omega-derived structured and crystallizes in the trigonal R-3 space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to six equivalent I(1) atoms to form edge-sharing ErI6 octahedra. In the second Er site, Er(2) is bonded to one Co(1), two equivalent I(1), and three equivalent I(2) atoms to form distorted ErCoI5 octahedra that share corners with three equivalent Er(2)CoI5 octahedra,  an edgeedge with one Er(1)I6 octahedra, and edges with five equivalent Er(2)CoI5 octahedra. The corner-sharing octahedral tilt angles range from 0-10°. Co(1) is bonded in an octahedral geometry to six equivalent Er(2) atoms. There are two inequivalent I sites. In the first I site, I(1) is bonded in a distorted T-shaped geometry to one Er(1) and two equivalent Er(2) atoms. In the second I site, I(2) is bonded in a 3-coordinate geometry to three equivalent Er(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Er7CoI12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.585
_cell_length_b   9.585
_cell_length_c   9.585
_cell_angle_alpha   106.862
_cell_angle_beta   106.862
_cell_angle_gamma   106.862
_symmetry_Int_Tables_number   1
_cell_volume   736.014
_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
  Er  Er0  1  0.500  0.500  0.500  1.0
  Er  Er1  1  0.286  0.091  0.022  1.0
  Er  Er2  1  0.022  0.286  0.091  1.0
  Er  Er3  1  0.091  0.022  0.286  1.0
  Er  Er4  1  0.714  0.909  0.978  1.0
  Er  Er5  1  0.978  0.714  0.909  1.0
  Er  Er6  1  0.909  0.978  0.714  1.0
  Co  Co7  1  0.000  0.000  0.000  1.0
  I  I8  1  0.466  0.160  0.388  1.0
  I  I9  1  0.388  0.466  0.160  1.0
  I  I10  1  0.160  0.388  0.466  1.0
  I  I11  1  0.534  0.840  0.612  1.0
  I  I12  1  0.612  0.534  0.840  1.0
  I  I13  1  0.840  0.612  0.534  1.0
  I  I14  1  0.324  0.774  0.929  1.0
  I  I15  1  0.929  0.324  0.774  1.0
  I  I16  1  0.774  0.929  0.324  1.0
  I  I17  1  0.676  0.226  0.071  1.0
  I  I18  1  0.071  0.676  0.226  1.0
  I  I19  1  0.226  0.071  0.676  1.0
[/CIF]
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