The compound described by Er2B2O5Cl2 crystallizes in the orthorhombic Pbam space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to one O(2), one O(3), one O(4), two equivalent O(1), and two equivalent Cl(2) atoms to form ErCl2O5 pentagonal bipyramids that share corners with two equivalent Er(2)Cl2O4 octahedra, corners with two equivalent Er(1)Cl2O5 pentagonal bipyramids, and  an edgeedge with one Er(1)Cl2O5 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 46-52°. In the second Er site, Er(2) is bonded to one O(2), one O(4), two equivalent O(5), and two equivalent Cl(1) atoms to form ErCl2O4 octahedra that share corners with two equivalent Er(2)Cl2O4 octahedra, corners with two equivalent Er(1)Cl2O5 pentagonal bipyramids, and  an edgeedge with one Er(2)Cl2O4 octahedra. The corner-sharing octahedral tilt angles are 8°. There are two inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(2), one O(3), and one O(4) atom. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(1), one O(3), and one O(5) atom. There are five inequivalent O sites. In the first O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Er(2) and one B(2) atom. In the second O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Er(1) and one B(2) atom. In the third O site, O(2) is bonded in a 3-coordinate geometry to one Er(1), one Er(2), and one B(1) atom. In the fourth O site, O(3) is bonded in a 3-coordinate geometry to one Er(1), one B(1), and one B(2) atom. In the fifth O site, O(4) is bonded in a 3-coordinate geometry to one Er(1), one Er(2), and one B(1) atom. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a linear geometry to two equivalent Er(2) atoms. In the second Cl site, Cl(2) is bonded in a linear geometry to two equivalent Er(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Er2B2Cl2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.288
_cell_length_b   10.088
_cell_length_c   14.901
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   794.819
_cell_formula_units_Z   4
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  0.531  0.121  1.0
  Er  Er1  1  0.500  0.969  0.621  1.0
  Er  Er2  1  0.500  0.431  0.391  1.0
  Er  Er3  1  0.500  0.069  0.891  1.0
  Er  Er4  1  0.500  0.469  0.879  1.0
  Er  Er5  1  0.500  0.931  0.109  1.0
  Er  Er6  1  0.500  0.031  0.379  1.0
  Er  Er7  1  0.500  0.569  0.609  1.0
  B  B8  1  0.500  0.302  0.733  1.0
  B  B9  1  0.500  0.255  0.065  1.0
  B  B10  1  0.500  0.745  0.935  1.0
  B  B11  1  0.500  0.198  0.233  1.0
  B  B12  1  0.500  0.755  0.435  1.0
  B  B13  1  0.500  0.245  0.565  1.0
  B  B14  1  0.500  0.698  0.267  1.0
  B  B15  1  0.500  0.802  0.767  1.0
  Cl  Cl16  1  0.000  0.413  0.390  1.0
  Cl  Cl17  1  0.000  0.007  0.369  1.0
  Cl  Cl18  1  0.000  0.913  0.110  1.0
  Cl  Cl19  1  0.000  0.507  0.131  1.0
  Cl  Cl20  1  0.000  0.493  0.869  1.0
  Cl  Cl21  1  0.000  0.587  0.610  1.0
  Cl  Cl22  1  0.000  0.087  0.890  1.0
  Cl  Cl23  1  0.000  0.993  0.631  1.0
  O  O24  1  0.500  0.867  0.488  1.0
  O  O25  1  0.500  0.244  0.319  1.0
  O  O26  1  0.500  0.787  0.341  1.0
  O  O27  1  0.500  0.563  0.276  1.0
  O  O28  1  0.500  0.937  0.776  1.0
  O  O29  1  0.500  0.063  0.224  1.0
  O  O30  1  0.500  0.713  0.841  1.0
  O  O31  1  0.500  0.133  0.512  1.0
  O  O32  1  0.500  0.744  0.181  1.0
  O  O33  1  0.500  0.213  0.659  1.0
  O  O34  1  0.500  0.256  0.819  1.0
  O  O35  1  0.500  0.628  0.464  1.0
  O  O36  1  0.500  0.756  0.681  1.0
  O  O37  1  0.500  0.372  0.536  1.0
  O  O38  1  0.500  0.287  0.159  1.0
  O  O39  1  0.500  0.128  0.036  1.0
  O  O40  1  0.500  0.633  0.988  1.0
  O  O41  1  0.500  0.367  0.012  1.0
  O  O42  1  0.500  0.872  0.964  1.0
  O  O43  1  0.500  0.437  0.724  1.0
[/CIF]
.
The compound described by Er2B2O5Cl2 crystallizes in the orthorhombic Pbam space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to one O(2), one O(3), one O(4), two equivalent O(1), and two equivalent Cl(2) atoms to form ErCl2O5 pentagonal bipyramids that share corners with two equivalent Er(2)Cl2O4 octahedra, corners with two equivalent Er(1)Cl2O5 pentagonal bipyramids, and  an edgeedge with one Er(1)Cl2O5 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 46-52°. In the second Er site, Er(2) is bonded to one O(2), one O(4), two equivalent O(5), and two equivalent Cl(1) atoms to form ErCl2O4 octahedra that share corners with two equivalent Er(2)Cl2O4 octahedra, corners with two equivalent Er(1)Cl2O5 pentagonal bipyramids, and  an edgeedge with one Er(2)Cl2O4 octahedra. The corner-sharing octahedral tilt angles are 8°. There are two inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(2), one O(3), and one O(4) atom. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(1), one O(3), and one O(5) atom. There are five inequivalent O sites. In the first O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Er(2) and one B(2) atom. In the second O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Er(1) and one B(2) atom. In the third O site, O(2) is bonded in a 3-coordinate geometry to one Er(1), one Er(2), and one B(1) atom. In the fourth O site, O(3) is bonded in a 3-coordinate geometry to one Er(1), one B(1), and one B(2) atom. In the fifth O site, O(4) is bonded in a 3-coordinate geometry to one Er(1), one Er(2), and one B(1) atom. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a linear geometry to two equivalent Er(2) atoms. In the second Cl site, Cl(2) is bonded in a linear geometry to two equivalent Er(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Er2B2Cl2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.288
_cell_length_b   10.088
_cell_length_c   14.901
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   794.819
_cell_formula_units_Z   4
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  0.531  0.121  1.0
  Er  Er1  1  0.500  0.969  0.621  1.0
  Er  Er2  1  0.500  0.431  0.391  1.0
  Er  Er3  1  0.500  0.069  0.891  1.0
  Er  Er4  1  0.500  0.469  0.879  1.0
  Er  Er5  1  0.500  0.931  0.109  1.0
  Er  Er6  1  0.500  0.031  0.379  1.0
  Er  Er7  1  0.500  0.569  0.609  1.0
  B  B8  1  0.500  0.302  0.733  1.0
  B  B9  1  0.500  0.255  0.065  1.0
  B  B10  1  0.500  0.745  0.935  1.0
  B  B11  1  0.500  0.198  0.233  1.0
  B  B12  1  0.500  0.755  0.435  1.0
  B  B13  1  0.500  0.245  0.565  1.0
  B  B14  1  0.500  0.698  0.267  1.0
  B  B15  1  0.500  0.802  0.767  1.0
  Cl  Cl16  1  0.000  0.413  0.390  1.0
  Cl  Cl17  1  0.000  0.007  0.369  1.0
  Cl  Cl18  1  0.000  0.913  0.110  1.0
  Cl  Cl19  1  0.000  0.507  0.131  1.0
  Cl  Cl20  1  0.000  0.493  0.869  1.0
  Cl  Cl21  1  0.000  0.587  0.610  1.0
  Cl  Cl22  1  0.000  0.087  0.890  1.0
  Cl  Cl23  1  0.000  0.993  0.631  1.0
  O  O24  1  0.500  0.867  0.488  1.0
  O  O25  1  0.500  0.244  0.319  1.0
  O  O26  1  0.500  0.787  0.341  1.0
  O  O27  1  0.500  0.563  0.276  1.0
  O  O28  1  0.500  0.937  0.776  1.0
  O  O29  1  0.500  0.063  0.224  1.0
  O  O30  1  0.500  0.713  0.841  1.0
  O  O31  1  0.500  0.133  0.512  1.0
  O  O32  1  0.500  0.744  0.181  1.0
  O  O33  1  0.500  0.213  0.659  1.0
  O  O34  1  0.500  0.256  0.819  1.0
  O  O35  1  0.500  0.628  0.464  1.0
  O  O36  1  0.500  0.756  0.681  1.0
  O  O37  1  0.500  0.372  0.536  1.0
  O  O38  1  0.500  0.287  0.159  1.0
  O  O39  1  0.500  0.128  0.036  1.0
  O  O40  1  0.500  0.633  0.988  1.0
  O  O41  1  0.500  0.367  0.012  1.0
  O  O42  1  0.500  0.872  0.964  1.0
  O  O43  1  0.500  0.437  0.724  1.0
[/CIF]
.