The compound described by Er4(B2O5)3 crystallizes in the monoclinic C2/c space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 8-coordinate geometry to one O(2), one O(8), two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms. In the second Er site, Er(2) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(7) atoms. There are three inequivalent B sites. In the first B site, B(1) is bonded to one O(1), one O(2), and two equivalent O(7) atoms to form a mixture of edge and corner-sharing BO4 tetrahedra. In the second B site, B(2) is bonded to one O(1), one O(2), one O(4), and one O(6) atom to form corner-sharing BO4 tetrahedra. In the third B site, B(3) is bonded to one O(3), one O(4), one O(5), and one O(8) atom to form corner-sharing BO4 tetrahedra. There are eight inequivalent O sites. In the first O site, O(8) is bonded in a 4-coordinate geometry to two equivalent Er(1) and two equivalent B(3) atoms. In the second O site, O(1) is bonded in a 3-coordinate geometry to one Er(2), one B(1), and one B(2) atom. In the third O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Er(1), one Er(2), one B(1), and one B(2) atom. In the fourth O site, O(3) is bonded in a 4-coordinate geometry to one Er(2), two equivalent Er(1), and one B(3) atom. In the fifth O site, O(4) is bonded in a 3-coordinate geometry to one Er(2), one B(2), and one B(3) atom. In the sixth O site, O(5) is bonded in a 4-coordinate geometry to one Er(2), two equivalent Er(1), and one B(3) atom. In the seventh O site, O(6) is bonded in a 4-coordinate geometry to one Er(2), two equivalent Er(1), and one B(2) atom. In the eighth O site, O(7) is bonded in a distorted L-shaped geometry to two equivalent Er(2) and two equivalent B(1) atoms. is represented by the CIF file [CIF]
data_Er4(B2O5)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.220
_cell_length_b   6.220
_cell_length_c   18.840
_cell_angle_alpha   83.955
_cell_angle_beta   83.955
_cell_angle_gamma   41.237
_symmetry_Int_Tables_number   1
_cell_volume   477.468
_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
  Er  Er0  1  0.653  0.072  0.302  1.0
  Er  Er1  1  0.667  0.068  0.099  1.0
  Er  Er2  1  0.932  0.333  0.401  1.0
  Er  Er3  1  0.928  0.347  0.198  1.0
  Er  Er4  1  0.072  0.653  0.802  1.0
  Er  Er5  1  0.068  0.667  0.599  1.0
  Er  Er6  1  0.333  0.932  0.901  1.0
  Er  Er7  1  0.347  0.928  0.698  1.0
  B  B8  1  0.640  0.021  0.474  1.0
  B  B9  1  0.197  0.609  0.413  1.0
  B  B10  1  0.204  0.660  0.194  1.0
  B  B11  1  0.609  0.197  0.913  1.0
  B  B12  1  0.660  0.204  0.694  1.0
  B  B13  1  0.979  0.360  0.026  1.0
  B  B14  1  0.021  0.640  0.974  1.0
  B  B15  1  0.340  0.796  0.306  1.0
  B  B16  1  0.391  0.803  0.087  1.0
  B  B17  1  0.796  0.340  0.806  1.0
  B  B18  1  0.803  0.391  0.587  1.0
  B  B19  1  0.360  0.979  0.526  1.0
  O  O20  1  0.994  0.751  0.479  1.0
  O  O21  1  0.543  0.289  0.430  1.0
  O  O22  1  0.535  0.336  0.197  1.0
  O  O23  1  0.160  0.812  0.121  1.0
  O  O24  1  0.812  0.160  0.621  1.0
  O  O25  1  0.951  0.685  0.204  1.0
  O  O26  1  0.751  0.994  0.979  1.0
  O  O27  1  0.289  0.543  0.930  1.0
  O  O28  1  0.336  0.535  0.697  1.0
  O  O29  1  0.077  0.560  0.362  1.0
  O  O30  1  0.505  0.912  0.451  1.0
  O  O31  1  0.560  0.077  0.862  1.0
  O  O32  1  0.685  0.951  0.704  1.0
  O  O33  1  0.912  0.505  0.951  1.0
  O  O34  1  0.088  0.495  0.049  1.0
  O  O35  1  0.315  0.049  0.296  1.0
  O  O36  1  0.440  0.923  0.138  1.0
  O  O37  1  0.495  0.088  0.549  1.0
  O  O38  1  0.923  0.440  0.638  1.0
  O  O39  1  0.664  0.465  0.303  1.0
  O  O40  1  0.711  0.457  0.070  1.0
  O  O41  1  0.249  0.006  0.021  1.0
  O  O42  1  0.049  0.315  0.796  1.0
  O  O43  1  0.188  0.840  0.379  1.0
  O  O44  1  0.840  0.188  0.879  1.0
  O  O45  1  0.465  0.664  0.803  1.0
  O  O46  1  0.869  0.131  0.750  1.0
  O  O47  1  0.131  0.869  0.250  1.0
  O  O48  1  0.457  0.711  0.570  1.0
  O  O49  1  0.006  0.249  0.521  1.0
[/CIF]
.
The compound described by Er4(B2O5)3 crystallizes in the monoclinic C2/c space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 8-coordinate geometry to one O(2), one O(8), two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms. In the second Er site, Er(2) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(7) atoms. There are three inequivalent B sites. In the first B site, B(1) is bonded to one O(1), one O(2), and two equivalent O(7) atoms to form a mixture of edge and corner-sharing BO4 tetrahedra. In the second B site, B(2) is bonded to one O(1), one O(2), one O(4), and one O(6) atom to form corner-sharing BO4 tetrahedra. In the third B site, B(3) is bonded to one O(3), one O(4), one O(5), and one O(8) atom to form corner-sharing BO4 tetrahedra. There are eight inequivalent O sites. In the first O site, O(8) is bonded in a 4-coordinate geometry to two equivalent Er(1) and two equivalent B(3) atoms. In the second O site, O(1) is bonded in a 3-coordinate geometry to one Er(2), one B(1), and one B(2) atom. In the third O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Er(1), one Er(2), one B(1), and one B(2) atom. In the fourth O site, O(3) is bonded in a 4-coordinate geometry to one Er(2), two equivalent Er(1), and one B(3) atom. In the fifth O site, O(4) is bonded in a 3-coordinate geometry to one Er(2), one B(2), and one B(3) atom. In the sixth O site, O(5) is bonded in a 4-coordinate geometry to one Er(2), two equivalent Er(1), and one B(3) atom. In the seventh O site, O(6) is bonded in a 4-coordinate geometry to one Er(2), two equivalent Er(1), and one B(2) atom. In the eighth O site, O(7) is bonded in a distorted L-shaped geometry to two equivalent Er(2) and two equivalent B(1) atoms. is represented by the CIF file [CIF]
data_Er4(B2O5)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.220
_cell_length_b   6.220
_cell_length_c   18.840
_cell_angle_alpha   83.955
_cell_angle_beta   83.955
_cell_angle_gamma   41.237
_symmetry_Int_Tables_number   1
_cell_volume   477.468
_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
  Er  Er0  1  0.653  0.072  0.302  1.0
  Er  Er1  1  0.667  0.068  0.099  1.0
  Er  Er2  1  0.932  0.333  0.401  1.0
  Er  Er3  1  0.928  0.347  0.198  1.0
  Er  Er4  1  0.072  0.653  0.802  1.0
  Er  Er5  1  0.068  0.667  0.599  1.0
  Er  Er6  1  0.333  0.932  0.901  1.0
  Er  Er7  1  0.347  0.928  0.698  1.0
  B  B8  1  0.640  0.021  0.474  1.0
  B  B9  1  0.197  0.609  0.413  1.0
  B  B10  1  0.204  0.660  0.194  1.0
  B  B11  1  0.609  0.197  0.913  1.0
  B  B12  1  0.660  0.204  0.694  1.0
  B  B13  1  0.979  0.360  0.026  1.0
  B  B14  1  0.021  0.640  0.974  1.0
  B  B15  1  0.340  0.796  0.306  1.0
  B  B16  1  0.391  0.803  0.087  1.0
  B  B17  1  0.796  0.340  0.806  1.0
  B  B18  1  0.803  0.391  0.587  1.0
  B  B19  1  0.360  0.979  0.526  1.0
  O  O20  1  0.994  0.751  0.479  1.0
  O  O21  1  0.543  0.289  0.430  1.0
  O  O22  1  0.535  0.336  0.197  1.0
  O  O23  1  0.160  0.812  0.121  1.0
  O  O24  1  0.812  0.160  0.621  1.0
  O  O25  1  0.951  0.685  0.204  1.0
  O  O26  1  0.751  0.994  0.979  1.0
  O  O27  1  0.289  0.543  0.930  1.0
  O  O28  1  0.336  0.535  0.697  1.0
  O  O29  1  0.077  0.560  0.362  1.0
  O  O30  1  0.505  0.912  0.451  1.0
  O  O31  1  0.560  0.077  0.862  1.0
  O  O32  1  0.685  0.951  0.704  1.0
  O  O33  1  0.912  0.505  0.951  1.0
  O  O34  1  0.088  0.495  0.049  1.0
  O  O35  1  0.315  0.049  0.296  1.0
  O  O36  1  0.440  0.923  0.138  1.0
  O  O37  1  0.495  0.088  0.549  1.0
  O  O38  1  0.923  0.440  0.638  1.0
  O  O39  1  0.664  0.465  0.303  1.0
  O  O40  1  0.711  0.457  0.070  1.0
  O  O41  1  0.249  0.006  0.021  1.0
  O  O42  1  0.049  0.315  0.796  1.0
  O  O43  1  0.188  0.840  0.379  1.0
  O  O44  1  0.840  0.188  0.879  1.0
  O  O45  1  0.465  0.664  0.803  1.0
  O  O46  1  0.869  0.131  0.750  1.0
  O  O47  1  0.131  0.869  0.250  1.0
  O  O48  1  0.457  0.711  0.570  1.0
  O  O49  1  0.006  0.249  0.521  1.0
[/CIF]
.