The material described by Sr4Cu2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(3), and three equivalent O(2) atoms. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to one O(4), two equivalent O(2), two equivalent O(3), and three equivalent O(1) atoms. Cu(1) is bonded to one O(1), one O(2), one O(4), and two equivalent O(3) atoms to form corner-sharing CuO5 square pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), three equivalent Sr(2), and one Cu(1) atom to form distorted OSr5Cu octahedra that share  a cornercorner with one O(2)Sr5Cu octahedra, corners with three equivalent O(4)Sr4Cu2 octahedra, corners with four equivalent O(1)Sr5Cu octahedra, corners with six equivalent O(3)Sr4Cu2 octahedra, edges with two equivalent O(1)Sr5Cu octahedra, edges with six equivalent O(2)Sr5Cu octahedra,  a faceface with one O(4)Sr4Cu2 octahedra, and faces with two equivalent O(3)Sr4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 5-67°. In the second O site, O(2) is bonded to two equivalent Sr(2), three equivalent Sr(1), and one Cu(1) atom to form distorted OSr5Cu octahedra that share  a cornercorner with one O(1)Sr5Cu octahedra, corners with three equivalent O(4)Sr4Cu2 octahedra, corners with four equivalent O(2)Sr5Cu octahedra, corners with six equivalent O(3)Sr4Cu2 octahedra, edges with two equivalent O(2)Sr5Cu octahedra, edges with six equivalent O(1)Sr5Cu octahedra,  a faceface with one O(4)Sr4Cu2 octahedra, and faces with two equivalent O(3)Sr4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 5-67°. In the third O site, O(3) is bonded to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Cu(1) atoms to form distorted OSr4Cu2 octahedra that share  a cornercorner with one O(4)Sr4Cu2 octahedra, corners with six equivalent O(1)Sr5Cu octahedra, corners with six equivalent O(2)Sr5Cu octahedra,  an edgeedge with one O(4)Sr4Cu2 octahedra,  a faceface with one O(4)Sr4Cu2 octahedra, faces with two equivalent O(3)Sr4Cu2 octahedra, faces with two equivalent O(1)Sr5Cu octahedra, and faces with two equivalent O(2)Sr5Cu octahedra. The corner-sharing octahedral tilt angles range from 2-67°. In the fourth O site, O(4) is bonded to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Cu(1) atoms to form OSr4Cu2 octahedra that share corners with two equivalent O(3)Sr4Cu2 octahedra, corners with six equivalent O(1)Sr5Cu octahedra, corners with six equivalent O(2)Sr5Cu octahedra, edges with two equivalent O(3)Sr4Cu2 octahedra, faces with two equivalent O(3)Sr4Cu2 octahedra, faces with two equivalent O(1)Sr5Cu octahedra, and faces with two equivalent O(2)Sr5Cu octahedra. The corner-sharing octahedral tilt angles range from 2-63°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sr4Cu2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.449
_cell_length_b   6.727
_cell_length_c   10.750
_cell_angle_alpha   66.317
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   360.862
_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
  Sr  Sr0  1  0.766  0.288  0.560  1.0
  Sr  Sr1  1  0.725  0.712  0.205  1.0
  Sr  Sr2  1  0.734  0.288  0.060  1.0
  Sr  Sr3  1  0.225  0.288  0.295  1.0
  Sr  Sr4  1  0.234  0.712  0.440  1.0
  Sr  Sr5  1  0.775  0.712  0.705  1.0
  Sr  Sr6  1  0.275  0.288  0.795  1.0
  Sr  Sr7  1  0.266  0.712  0.940  1.0
  Cu  Cu8  1  0.743  0.999  0.383  1.0
  Cu  Cu9  1  0.257  0.001  0.617  1.0
  Cu  Cu10  1  0.757  0.999  0.883  1.0
  Cu  Cu11  1  0.243  0.001  0.117  1.0
  O  O12  1  0.726  0.308  0.311  1.0
  O  O13  1  0.735  0.691  0.464  1.0
  O  O14  1  0.493  0.999  0.274  1.0
  O  O15  1  0.000  0.000  0.500  1.0
  O  O16  1  0.500  0.000  0.000  1.0
  O  O17  1  0.993  0.001  0.226  1.0
  O  O18  1  0.265  0.309  0.536  1.0
  O  O19  1  0.507  0.001  0.726  1.0
  O  O20  1  0.226  0.692  0.189  1.0
  O  O21  1  0.765  0.691  0.964  1.0
  O  O22  1  0.774  0.308  0.811  1.0
  O  O23  1  0.235  0.309  0.036  1.0
  O  O24  1  0.274  0.692  0.689  1.0
  O  O25  1  0.007  0.999  0.774  1.0
[/CIF]
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The material described by Sr4Cu2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(3), and three equivalent O(2) atoms. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to one O(4), two equivalent O(2), two equivalent O(3), and three equivalent O(1) atoms. Cu(1) is bonded to one O(1), one O(2), one O(4), and two equivalent O(3) atoms to form corner-sharing CuO5 square pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), three equivalent Sr(2), and one Cu(1) atom to form distorted OSr5Cu octahedra that share  a cornercorner with one O(2)Sr5Cu octahedra, corners with three equivalent O(4)Sr4Cu2 octahedra, corners with four equivalent O(1)Sr5Cu octahedra, corners with six equivalent O(3)Sr4Cu2 octahedra, edges with two equivalent O(1)Sr5Cu octahedra, edges with six equivalent O(2)Sr5Cu octahedra,  a faceface with one O(4)Sr4Cu2 octahedra, and faces with two equivalent O(3)Sr4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 5-67°. In the second O site, O(2) is bonded to two equivalent Sr(2), three equivalent Sr(1), and one Cu(1) atom to form distorted OSr5Cu octahedra that share  a cornercorner with one O(1)Sr5Cu octahedra, corners with three equivalent O(4)Sr4Cu2 octahedra, corners with four equivalent O(2)Sr5Cu octahedra, corners with six equivalent O(3)Sr4Cu2 octahedra, edges with two equivalent O(2)Sr5Cu octahedra, edges with six equivalent O(1)Sr5Cu octahedra,  a faceface with one O(4)Sr4Cu2 octahedra, and faces with two equivalent O(3)Sr4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 5-67°. In the third O site, O(3) is bonded to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Cu(1) atoms to form distorted OSr4Cu2 octahedra that share  a cornercorner with one O(4)Sr4Cu2 octahedra, corners with six equivalent O(1)Sr5Cu octahedra, corners with six equivalent O(2)Sr5Cu octahedra,  an edgeedge with one O(4)Sr4Cu2 octahedra,  a faceface with one O(4)Sr4Cu2 octahedra, faces with two equivalent O(3)Sr4Cu2 octahedra, faces with two equivalent O(1)Sr5Cu octahedra, and faces with two equivalent O(2)Sr5Cu octahedra. The corner-sharing octahedral tilt angles range from 2-67°. In the fourth O site, O(4) is bonded to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Cu(1) atoms to form OSr4Cu2 octahedra that share corners with two equivalent O(3)Sr4Cu2 octahedra, corners with six equivalent O(1)Sr5Cu octahedra, corners with six equivalent O(2)Sr5Cu octahedra, edges with two equivalent O(3)Sr4Cu2 octahedra, faces with two equivalent O(3)Sr4Cu2 octahedra, faces with two equivalent O(1)Sr5Cu octahedra, and faces with two equivalent O(2)Sr5Cu octahedra. The corner-sharing octahedral tilt angles range from 2-63°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sr4Cu2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.449
_cell_length_b   6.727
_cell_length_c   10.750
_cell_angle_alpha   66.317
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   360.862
_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
  Sr  Sr0  1  0.766  0.288  0.560  1.0
  Sr  Sr1  1  0.725  0.712  0.205  1.0
  Sr  Sr2  1  0.734  0.288  0.060  1.0
  Sr  Sr3  1  0.225  0.288  0.295  1.0
  Sr  Sr4  1  0.234  0.712  0.440  1.0
  Sr  Sr5  1  0.775  0.712  0.705  1.0
  Sr  Sr6  1  0.275  0.288  0.795  1.0
  Sr  Sr7  1  0.266  0.712  0.940  1.0
  Cu  Cu8  1  0.743  0.999  0.383  1.0
  Cu  Cu9  1  0.257  0.001  0.617  1.0
  Cu  Cu10  1  0.757  0.999  0.883  1.0
  Cu  Cu11  1  0.243  0.001  0.117  1.0
  O  O12  1  0.726  0.308  0.311  1.0
  O  O13  1  0.735  0.691  0.464  1.0
  O  O14  1  0.493  0.999  0.274  1.0
  O  O15  1  0.000  0.000  0.500  1.0
  O  O16  1  0.500  0.000  0.000  1.0
  O  O17  1  0.993  0.001  0.226  1.0
  O  O18  1  0.265  0.309  0.536  1.0
  O  O19  1  0.507  0.001  0.726  1.0
  O  O20  1  0.226  0.692  0.189  1.0
  O  O21  1  0.765  0.691  0.964  1.0
  O  O22  1  0.774  0.308  0.811  1.0
  O  O23  1  0.235  0.309  0.036  1.0
  O  O24  1  0.274  0.692  0.689  1.0
  O  O25  1  0.007  0.999  0.774  1.0
[/CIF]
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