The structure described by TlSr2CaCu2O7 crystallizes in the tetragonal P4/mmm space group. Sr(1) is bonded in a 9-coordinate geometry to one O(3), four equivalent O(1), and four equivalent O(2) atoms. Ca(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. Cu(1) is bonded to one O(2) and four equivalent O(1) atoms to form CuO5 square pyramids that share  a cornercorner with one Tl(1)O6 octahedra and corners with four equivalent Cu(1)O5 square pyramids. The corner-sharing octahedra are not tilted. Tl(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form TlO6 octahedra that share corners with four equivalent Tl(1)O6 octahedra, corners with two equivalent Cu(1)O5 square pyramids, and edges with four equivalent Tl(1)O6 octahedra. The corner-sharing octahedra are not tilted. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Ca(1), and two equivalent Cu(1) atoms to form distorted OSr2Ca2Cu2 octahedra that share corners with two equivalent O(3)Sr2Tl4 octahedra, corners with four equivalent O(2)Sr4TlCu octahedra, corners with eight equivalent O(1)Sr2Ca2Cu2 octahedra, edges with three equivalent O(1)Sr2Ca2Cu2 octahedra, faces with two equivalent O(2)Sr4TlCu octahedra, and faces with four equivalent O(1)Sr2Ca2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-66°. In the second O site, O(2) is bonded to four equivalent Sr(1), one Cu(1), and one Tl(1) atom to form distorted OSr4TlCu octahedra that share corners with five equivalent O(2)Sr4TlCu octahedra, corners with eight equivalent O(1)Sr2Ca2Cu2 octahedra, edges with four equivalent O(3)Sr2Tl4 octahedra, edges with four equivalent O(2)Sr4TlCu octahedra, and faces with four equivalent O(1)Sr2Ca2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-53°. In the third O site, O(3) is bonded to two equivalent Sr(1) and four equivalent Tl(1) atoms to form OSr2Tl4 octahedra that share corners with four equivalent O(3)Sr2Tl4 octahedra, corners with eight equivalent O(1)Sr2Ca2Cu2 octahedra, edges with four equivalent O(3)Sr2Tl4 octahedra, and edges with eight equivalent O(2)Sr4TlCu octahedra. The corner-sharing octahedral tilt angles range from 0-43°. is represented by the CIF file [CIF]
data_Sr2CaTlCu2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.782
_cell_length_b   3.782
_cell_length_c   12.291
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   175.795
_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  0.500  0.500  0.209  1.0
  Sr  Sr1  1  0.500  0.500  0.791  1.0
  Ca  Ca2  1  0.500  0.500  0.500  1.0
  Tl  Tl3  1  0.000  0.000  0.000  1.0
  Cu  Cu4  1  0.000  0.000  0.357  1.0
  Cu  Cu5  1  0.000  0.000  0.643  1.0
  O  O6  1  0.500  0.000  0.628  1.0
  O  O7  1  0.000  0.500  0.628  1.0
  O  O8  1  0.500  0.000  0.372  1.0
  O  O9  1  0.000  0.500  0.372  1.0
  O  O10  1  0.000  0.000  0.828  1.0
  O  O11  1  0.000  0.000  0.172  1.0
  O  O12  1  0.500  0.500  0.000  1.0
[/CIF]
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The structure described by TlSr2CaCu2O7 crystallizes in the tetragonal P4/mmm space group. Sr(1) is bonded in a 9-coordinate geometry to one O(3), four equivalent O(1), and four equivalent O(2) atoms. Ca(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. Cu(1) is bonded to one O(2) and four equivalent O(1) atoms to form CuO5 square pyramids that share  a cornercorner with one Tl(1)O6 octahedra and corners with four equivalent Cu(1)O5 square pyramids. The corner-sharing octahedra are not tilted. Tl(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form TlO6 octahedra that share corners with four equivalent Tl(1)O6 octahedra, corners with two equivalent Cu(1)O5 square pyramids, and edges with four equivalent Tl(1)O6 octahedra. The corner-sharing octahedra are not tilted. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Ca(1), and two equivalent Cu(1) atoms to form distorted OSr2Ca2Cu2 octahedra that share corners with two equivalent O(3)Sr2Tl4 octahedra, corners with four equivalent O(2)Sr4TlCu octahedra, corners with eight equivalent O(1)Sr2Ca2Cu2 octahedra, edges with three equivalent O(1)Sr2Ca2Cu2 octahedra, faces with two equivalent O(2)Sr4TlCu octahedra, and faces with four equivalent O(1)Sr2Ca2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-66°. In the second O site, O(2) is bonded to four equivalent Sr(1), one Cu(1), and one Tl(1) atom to form distorted OSr4TlCu octahedra that share corners with five equivalent O(2)Sr4TlCu octahedra, corners with eight equivalent O(1)Sr2Ca2Cu2 octahedra, edges with four equivalent O(3)Sr2Tl4 octahedra, edges with four equivalent O(2)Sr4TlCu octahedra, and faces with four equivalent O(1)Sr2Ca2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-53°. In the third O site, O(3) is bonded to two equivalent Sr(1) and four equivalent Tl(1) atoms to form OSr2Tl4 octahedra that share corners with four equivalent O(3)Sr2Tl4 octahedra, corners with eight equivalent O(1)Sr2Ca2Cu2 octahedra, edges with four equivalent O(3)Sr2Tl4 octahedra, and edges with eight equivalent O(2)Sr4TlCu octahedra. The corner-sharing octahedral tilt angles range from 0-43°. is represented by the CIF file [CIF]
data_Sr2CaTlCu2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.782
_cell_length_b   3.782
_cell_length_c   12.291
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   175.795
_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  0.500  0.500  0.209  1.0
  Sr  Sr1  1  0.500  0.500  0.791  1.0
  Ca  Ca2  1  0.500  0.500  0.500  1.0
  Tl  Tl3  1  0.000  0.000  0.000  1.0
  Cu  Cu4  1  0.000  0.000  0.357  1.0
  Cu  Cu5  1  0.000  0.000  0.643  1.0
  O  O6  1  0.500  0.000  0.628  1.0
  O  O7  1  0.000  0.500  0.628  1.0
  O  O8  1  0.500  0.000  0.372  1.0
  O  O9  1  0.000  0.500  0.372  1.0
  O  O10  1  0.000  0.000  0.828  1.0
  O  O11  1  0.000  0.000  0.172  1.0
  O  O12  1  0.500  0.500  0.000  1.0
[/CIF]
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