The compound described by Sr2ErCu2(BiO4)2 crystallizes in the tetragonal I4/mmm space group. Sr(1) is bonded in a 9-coordinate geometry to one O(2), four equivalent O(1), and four equivalent O(3) atoms. Er(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. Cu(1) is bonded to one O(3) and four equivalent O(1) atoms to form distorted CuO5 square pyramids that share  a cornercorner with one Bi(1)O6 octahedra and corners with four equivalent Cu(1)O5 square pyramids. The corner-sharing octahedra are not tilted. Bi(1) is bonded to one O(3) and five equivalent O(2) atoms to form distorted BiO6 octahedra that share corners with four equivalent Bi(1)O6 octahedra,  a cornercorner with one Cu(1)O5 square pyramid, and edges with eight equivalent Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles are 3°. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Er(1), and two equivalent Cu(1) atoms to form distorted OSr2Er2Cu2 octahedra that share corners with two equivalent O(2)SrBi5 octahedra, corners with four equivalent O(3)Sr4CuBi octahedra, corners with eight equivalent O(1)Sr2Er2Cu2 octahedra, edges with three equivalent O(1)Sr2Er2Cu2 octahedra, faces with two equivalent O(3)Sr4CuBi octahedra, and faces with four equivalent O(1)Sr2Er2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-68°. In the second O site, O(2) is bonded to one Sr(1) and five equivalent Bi(1) atoms to form OSrBi5 octahedra that share  a cornercorner with one O(3)Sr4CuBi octahedra, corners with four equivalent O(1)Sr2Er2Cu2 octahedra, corners with four equivalent O(2)SrBi5 octahedra, edges with four equivalent O(3)Sr4CuBi octahedra, and edges with eight equivalent O(2)SrBi5 octahedra. The corner-sharing octahedral tilt angles range from 0-43°. In the third O site, O(3) is bonded to four equivalent Sr(1), one Cu(1), and one Bi(1) atom to form distorted OSr4CuBi octahedra that share  a cornercorner with one O(2)SrBi5 octahedra, corners with four equivalent O(3)Sr4CuBi octahedra, corners with eight equivalent O(1)Sr2Er2Cu2 octahedra, edges with four equivalent O(3)Sr4CuBi octahedra, edges with four equivalent O(2)SrBi5 octahedra, and faces with four equivalent O(1)Sr2Er2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-51°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sr2ErCu2(BiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   15.460
_cell_length_b   15.460
_cell_length_c   15.460
_cell_angle_alpha   165.955
_cell_angle_beta   165.955
_cell_angle_gamma   19.914
_symmetry_Int_Tables_number   1
_cell_volume   217.624
_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
  Sr  Sr0  1  0.115  0.115  0.000  1.0
  Sr  Sr1  1  0.885  0.885  0.000  1.0
  Er  Er2  1  0.000  0.000  0.000  1.0
  Cu  Cu3  1  0.448  0.448  0.000  1.0
  Cu  Cu4  1  0.552  0.552  0.000  1.0
  Bi  Bi5  1  0.296  0.296  0.000  1.0
  Bi  Bi6  1  0.704  0.704  0.000  1.0
  O  O7  1  0.548  0.048  0.500  1.0
  O  O8  1  0.452  0.952  0.500  1.0
  O  O9  1  0.048  0.548  0.500  1.0
  O  O10  1  0.952  0.452  0.500  1.0
  O  O11  1  0.202  0.202  0.000  1.0
  O  O12  1  0.798  0.798  0.000  1.0
  O  O13  1  0.365  0.365  0.000  1.0
  O  O14  1  0.635  0.635  0.000  1.0
[/CIF]
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The compound described by Sr2ErCu2(BiO4)2 crystallizes in the tetragonal I4/mmm space group. Sr(1) is bonded in a 9-coordinate geometry to one O(2), four equivalent O(1), and four equivalent O(3) atoms. Er(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. Cu(1) is bonded to one O(3) and four equivalent O(1) atoms to form distorted CuO5 square pyramids that share  a cornercorner with one Bi(1)O6 octahedra and corners with four equivalent Cu(1)O5 square pyramids. The corner-sharing octahedra are not tilted. Bi(1) is bonded to one O(3) and five equivalent O(2) atoms to form distorted BiO6 octahedra that share corners with four equivalent Bi(1)O6 octahedra,  a cornercorner with one Cu(1)O5 square pyramid, and edges with eight equivalent Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles are 3°. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Er(1), and two equivalent Cu(1) atoms to form distorted OSr2Er2Cu2 octahedra that share corners with two equivalent O(2)SrBi5 octahedra, corners with four equivalent O(3)Sr4CuBi octahedra, corners with eight equivalent O(1)Sr2Er2Cu2 octahedra, edges with three equivalent O(1)Sr2Er2Cu2 octahedra, faces with two equivalent O(3)Sr4CuBi octahedra, and faces with four equivalent O(1)Sr2Er2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-68°. In the second O site, O(2) is bonded to one Sr(1) and five equivalent Bi(1) atoms to form OSrBi5 octahedra that share  a cornercorner with one O(3)Sr4CuBi octahedra, corners with four equivalent O(1)Sr2Er2Cu2 octahedra, corners with four equivalent O(2)SrBi5 octahedra, edges with four equivalent O(3)Sr4CuBi octahedra, and edges with eight equivalent O(2)SrBi5 octahedra. The corner-sharing octahedral tilt angles range from 0-43°. In the third O site, O(3) is bonded to four equivalent Sr(1), one Cu(1), and one Bi(1) atom to form distorted OSr4CuBi octahedra that share  a cornercorner with one O(2)SrBi5 octahedra, corners with four equivalent O(3)Sr4CuBi octahedra, corners with eight equivalent O(1)Sr2Er2Cu2 octahedra, edges with four equivalent O(3)Sr4CuBi octahedra, edges with four equivalent O(2)SrBi5 octahedra, and faces with four equivalent O(1)Sr2Er2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-51°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sr2ErCu2(BiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   15.460
_cell_length_b   15.460
_cell_length_c   15.460
_cell_angle_alpha   165.955
_cell_angle_beta   165.955
_cell_angle_gamma   19.914
_symmetry_Int_Tables_number   1
_cell_volume   217.624
_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
  Sr  Sr0  1  0.115  0.115  0.000  1.0
  Sr  Sr1  1  0.885  0.885  0.000  1.0
  Er  Er2  1  0.000  0.000  0.000  1.0
  Cu  Cu3  1  0.448  0.448  0.000  1.0
  Cu  Cu4  1  0.552  0.552  0.000  1.0
  Bi  Bi5  1  0.296  0.296  0.000  1.0
  Bi  Bi6  1  0.704  0.704  0.000  1.0
  O  O7  1  0.548  0.048  0.500  1.0
  O  O8  1  0.452  0.952  0.500  1.0
  O  O9  1  0.048  0.548  0.500  1.0
  O  O10  1  0.952  0.452  0.500  1.0
  O  O11  1  0.202  0.202  0.000  1.0
  O  O12  1  0.798  0.798  0.000  1.0
  O  O13  1  0.365  0.365  0.000  1.0
  O  O14  1  0.635  0.635  0.000  1.0
[/CIF]
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