The compound described by Er2Cu2O5 is Spinel-like structured and crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(5) atoms to form a mixture of distorted corner and edge-sharing ErO6 octahedra. The corner-sharing octahedral tilt angles range from 21-64°. In the second Er site, Er(2) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form a mixture of corner and edge-sharing ErO6 octahedra. The corner-sharing octahedral tilt angles range from 21-64°. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a rectangular see-saw-like geometry to one O(2), one O(3), one O(4), and one O(5) atom. In the second Cu site, Cu(2) is bonded in a rectangular see-saw-like geometry to one O(1), one O(2), one O(3), and one O(4) atom. There are five inequivalent O sites. In the first O site, O(5) is bonded to one Er(2), two equivalent Er(1), and one Cu(1) atom to form OEr3Cu tetrahedra that share corners with two equivalent O(5)Er3Cu tetrahedra, corners with four equivalent O(1)Er3Cu tetrahedra, corners with three equivalent O(2)Er2Cu2 trigonal pyramids, corners with three equivalent O(4)Er2Cu2 trigonal pyramids, and  an edgeedge with one O(2)Er2Cu2 trigonal pyramid. In the second O site, O(1) is bonded to one Er(1), two equivalent Er(2), and one Cu(2) atom to form OEr3Cu tetrahedra that share corners with two equivalent O(1)Er3Cu tetrahedra, corners with four equivalent O(5)Er3Cu tetrahedra, corners with three equivalent O(2)Er2Cu2 trigonal pyramids, corners with three equivalent O(4)Er2Cu2 trigonal pyramids, and  an edgeedge with one O(4)Er2Cu2 trigonal pyramid. In the third O site, O(2) is bonded to two equivalent Er(1), one Cu(1), and one Cu(2) atom to form OEr2Cu2 trigonal pyramids that share corners with three equivalent O(1)Er3Cu tetrahedra, corners with three equivalent O(5)Er3Cu tetrahedra, corners with two equivalent O(2)Er2Cu2 trigonal pyramids,  an edgeedge with one O(5)Er3Cu tetrahedra, and  an edgeedge with one O(4)Er2Cu2 trigonal pyramid. In the fourth O site, O(3) is bonded in a distorted see-saw-like geometry to one Er(1), one Er(2), one Cu(1), and one Cu(2) atom. In the fifth O site, O(4) is bonded to two equivalent Er(2), one Cu(1), and one Cu(2) atom to form OEr2Cu2 trigonal pyramids that share corners with three equivalent O(1)Er3Cu tetrahedra, corners with three equivalent O(5)Er3Cu tetrahedra, corners with two equivalent O(4)Er2Cu2 trigonal pyramids,  an edgeedge with one O(1)Er3Cu tetrahedra, and  an edgeedge with one O(2)Er2Cu2 trigonal pyramid. is represented by the CIF card [CIF]
data_Er2Cu2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.489
_cell_length_b   10.847
_cell_length_c   12.485
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   472.465
_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  0.278  0.543  0.827  1.0
  Er  Er1  1  0.722  0.457  0.327  1.0
  Er  Er2  1  0.222  0.043  0.827  1.0
  Er  Er3  1  0.778  0.957  0.327  1.0
  Er  Er4  1  0.280  0.709  0.499  1.0
  Er  Er5  1  0.720  0.291  0.999  1.0
  Er  Er6  1  0.220  0.209  0.499  1.0
  Er  Er7  1  0.780  0.791  0.999  1.0
  Cu  Cu8  1  0.846  0.763  0.716  1.0
  Cu  Cu9  1  0.154  0.237  0.216  1.0
  Cu  Cu10  1  0.654  0.263  0.716  1.0
  Cu  Cu11  1  0.346  0.737  0.216  1.0
  Cu  Cu12  1  0.841  0.490  0.609  1.0
  Cu  Cu13  1  0.159  0.510  0.109  1.0
  Cu  Cu14  1  0.659  0.990  0.609  1.0
  Cu  Cu15  1  0.341  0.010  0.109  1.0
  O  O16  1  0.274  0.922  0.970  1.0
  O  O17  1  0.726  0.078  0.469  1.0
  O  O18  1  0.226  0.422  0.970  1.0
  O  O19  1  0.774  0.578  0.469  1.0
  O  O20  1  0.723  0.930  0.761  1.0
  O  O21  1  0.277  0.070  0.261  1.0
  O  O22  1  0.777  0.430  0.761  1.0
  O  O23  1  0.223  0.570  0.261  1.0
  O  O24  1  0.162  0.626  0.663  1.0
  O  O25  1  0.838  0.374  0.163  1.0
  O  O26  1  0.338  0.126  0.663  1.0
  O  O27  1  0.662  0.874  0.163  1.0
  O  O28  1  0.783  0.823  0.563  1.0
  O  O29  1  0.217  0.177  0.063  1.0
  O  O30  1  0.717  0.323  0.563  1.0
  O  O31  1  0.283  0.677  0.063  1.0
  O  O32  1  0.276  0.826  0.355  1.0
  O  O33  1  0.724  0.174  0.855  1.0
  O  O34  1  0.224  0.326  0.355  1.0
  O  O35  1  0.776  0.674  0.855  1.0
[/CIF]
.
The compound described by Er2Cu2O5 is Spinel-like structured and crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(5) atoms to form a mixture of distorted corner and edge-sharing ErO6 octahedra. The corner-sharing octahedral tilt angles range from 21-64°. In the second Er site, Er(2) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form a mixture of corner and edge-sharing ErO6 octahedra. The corner-sharing octahedral tilt angles range from 21-64°. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a rectangular see-saw-like geometry to one O(2), one O(3), one O(4), and one O(5) atom. In the second Cu site, Cu(2) is bonded in a rectangular see-saw-like geometry to one O(1), one O(2), one O(3), and one O(4) atom. There are five inequivalent O sites. In the first O site, O(5) is bonded to one Er(2), two equivalent Er(1), and one Cu(1) atom to form OEr3Cu tetrahedra that share corners with two equivalent O(5)Er3Cu tetrahedra, corners with four equivalent O(1)Er3Cu tetrahedra, corners with three equivalent O(2)Er2Cu2 trigonal pyramids, corners with three equivalent O(4)Er2Cu2 trigonal pyramids, and  an edgeedge with one O(2)Er2Cu2 trigonal pyramid. In the second O site, O(1) is bonded to one Er(1), two equivalent Er(2), and one Cu(2) atom to form OEr3Cu tetrahedra that share corners with two equivalent O(1)Er3Cu tetrahedra, corners with four equivalent O(5)Er3Cu tetrahedra, corners with three equivalent O(2)Er2Cu2 trigonal pyramids, corners with three equivalent O(4)Er2Cu2 trigonal pyramids, and  an edgeedge with one O(4)Er2Cu2 trigonal pyramid. In the third O site, O(2) is bonded to two equivalent Er(1), one Cu(1), and one Cu(2) atom to form OEr2Cu2 trigonal pyramids that share corners with three equivalent O(1)Er3Cu tetrahedra, corners with three equivalent O(5)Er3Cu tetrahedra, corners with two equivalent O(2)Er2Cu2 trigonal pyramids,  an edgeedge with one O(5)Er3Cu tetrahedra, and  an edgeedge with one O(4)Er2Cu2 trigonal pyramid. In the fourth O site, O(3) is bonded in a distorted see-saw-like geometry to one Er(1), one Er(2), one Cu(1), and one Cu(2) atom. In the fifth O site, O(4) is bonded to two equivalent Er(2), one Cu(1), and one Cu(2) atom to form OEr2Cu2 trigonal pyramids that share corners with three equivalent O(1)Er3Cu tetrahedra, corners with three equivalent O(5)Er3Cu tetrahedra, corners with two equivalent O(4)Er2Cu2 trigonal pyramids,  an edgeedge with one O(1)Er3Cu tetrahedra, and  an edgeedge with one O(2)Er2Cu2 trigonal pyramid. is represented by the CIF card [CIF]
data_Er2Cu2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.489
_cell_length_b   10.847
_cell_length_c   12.485
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   472.465
_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  0.278  0.543  0.827  1.0
  Er  Er1  1  0.722  0.457  0.327  1.0
  Er  Er2  1  0.222  0.043  0.827  1.0
  Er  Er3  1  0.778  0.957  0.327  1.0
  Er  Er4  1  0.280  0.709  0.499  1.0
  Er  Er5  1  0.720  0.291  0.999  1.0
  Er  Er6  1  0.220  0.209  0.499  1.0
  Er  Er7  1  0.780  0.791  0.999  1.0
  Cu  Cu8  1  0.846  0.763  0.716  1.0
  Cu  Cu9  1  0.154  0.237  0.216  1.0
  Cu  Cu10  1  0.654  0.263  0.716  1.0
  Cu  Cu11  1  0.346  0.737  0.216  1.0
  Cu  Cu12  1  0.841  0.490  0.609  1.0
  Cu  Cu13  1  0.159  0.510  0.109  1.0
  Cu  Cu14  1  0.659  0.990  0.609  1.0
  Cu  Cu15  1  0.341  0.010  0.109  1.0
  O  O16  1  0.274  0.922  0.970  1.0
  O  O17  1  0.726  0.078  0.469  1.0
  O  O18  1  0.226  0.422  0.970  1.0
  O  O19  1  0.774  0.578  0.469  1.0
  O  O20  1  0.723  0.930  0.761  1.0
  O  O21  1  0.277  0.070  0.261  1.0
  O  O22  1  0.777  0.430  0.761  1.0
  O  O23  1  0.223  0.570  0.261  1.0
  O  O24  1  0.162  0.626  0.663  1.0
  O  O25  1  0.838  0.374  0.163  1.0
  O  O26  1  0.338  0.126  0.663  1.0
  O  O27  1  0.662  0.874  0.163  1.0
  O  O28  1  0.783  0.823  0.563  1.0
  O  O29  1  0.217  0.177  0.063  1.0
  O  O30  1  0.717  0.323  0.563  1.0
  O  O31  1  0.283  0.677  0.063  1.0
  O  O32  1  0.276  0.826  0.355  1.0
  O  O33  1  0.724  0.174  0.855  1.0
  O  O34  1  0.224  0.326  0.355  1.0
  O  O35  1  0.776  0.674  0.855  1.0
[/CIF]
.