The structure described by Sr2EuTa(CuO4)2 crystallizes in the tetragonal P4/mmm space group. Sr(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms to form distorted SrO12 cuboctahedra that share corners with eight equivalent Sr(1)O12 cuboctahedra, faces with five equivalent Sr(1)O12 cuboctahedra, faces with four equivalent Ta(1)O6 octahedra, and faces with four equivalent Cu(1)O5 square pyramids. Eu(1) is bonded in a body-centered cubic geometry to eight equivalent O(3) atoms. Ta(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form TaO6 octahedra that share corners with four equivalent Ta(1)O6 octahedra, corners with two equivalent Cu(1)O5 square pyramids, and faces with eight equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. Cu(1) is bonded to one O(1) and four equivalent O(3) atoms to form CuO5 square pyramids that share  a cornercorner with one Ta(1)O6 octahedra, corners with four equivalent Cu(1)O5 square pyramids, and faces with four equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Sr(1), one Ta(1), and one Cu(1) atom to form distorted OSr4TaCu octahedra that share corners with five equivalent O(1)Sr4TaCu octahedra, corners with eight equivalent O(3)Sr2Eu2Cu2 octahedra, edges with four equivalent O(1)Sr4TaCu octahedra, and faces with four equivalent O(3)Sr2Eu2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-54°. In the second O site, O(2) is bonded in a linear geometry to four equivalent Sr(1) and two equivalent Ta(1) atoms. In the third O site, O(3) is bonded to two equivalent Sr(1), two equivalent Eu(1), and two equivalent Cu(1) atoms to form distorted OSr2Eu2Cu2 octahedra that share corners with four equivalent O(1)Sr4TaCu octahedra, corners with eight equivalent O(3)Sr2Eu2Cu2 octahedra, edges with three equivalent O(3)Sr2Eu2Cu2 octahedra, faces with two equivalent O(1)Sr4TaCu octahedra, and faces with four equivalent O(3)Sr2Eu2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-67°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sr2EuTa(CuO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.944
_cell_length_b   3.944
_cell_length_c   11.782
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   183.240
_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  0.200  1.0
  Sr  Sr1  1  0.500  0.500  0.800  1.0
  Eu  Eu2  1  0.500  0.500  0.500  1.0
  Ta  Ta3  1  0.000  0.000  0.000  1.0
  Cu  Cu4  1  0.000  0.000  0.356  1.0
  Cu  Cu5  1  0.000  0.000  0.644  1.0
  O  O6  1  0.000  0.000  0.168  1.0
  O  O7  1  0.000  0.000  0.832  1.0
  O  O8  1  0.000  0.500  0.000  1.0
  O  O9  1  0.500  0.000  0.000  1.0
  O  O10  1  0.000  0.500  0.367  1.0
  O  O11  1  0.000  0.500  0.633  1.0
  O  O12  1  0.500  0.000  0.367  1.0
  O  O13  1  0.500  0.000  0.633  1.0
[/CIF]
.
The structure described by Sr2EuTa(CuO4)2 crystallizes in the tetragonal P4/mmm space group. Sr(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms to form distorted SrO12 cuboctahedra that share corners with eight equivalent Sr(1)O12 cuboctahedra, faces with five equivalent Sr(1)O12 cuboctahedra, faces with four equivalent Ta(1)O6 octahedra, and faces with four equivalent Cu(1)O5 square pyramids. Eu(1) is bonded in a body-centered cubic geometry to eight equivalent O(3) atoms. Ta(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form TaO6 octahedra that share corners with four equivalent Ta(1)O6 octahedra, corners with two equivalent Cu(1)O5 square pyramids, and faces with eight equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. Cu(1) is bonded to one O(1) and four equivalent O(3) atoms to form CuO5 square pyramids that share  a cornercorner with one Ta(1)O6 octahedra, corners with four equivalent Cu(1)O5 square pyramids, and faces with four equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Sr(1), one Ta(1), and one Cu(1) atom to form distorted OSr4TaCu octahedra that share corners with five equivalent O(1)Sr4TaCu octahedra, corners with eight equivalent O(3)Sr2Eu2Cu2 octahedra, edges with four equivalent O(1)Sr4TaCu octahedra, and faces with four equivalent O(3)Sr2Eu2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-54°. In the second O site, O(2) is bonded in a linear geometry to four equivalent Sr(1) and two equivalent Ta(1) atoms. In the third O site, O(3) is bonded to two equivalent Sr(1), two equivalent Eu(1), and two equivalent Cu(1) atoms to form distorted OSr2Eu2Cu2 octahedra that share corners with four equivalent O(1)Sr4TaCu octahedra, corners with eight equivalent O(3)Sr2Eu2Cu2 octahedra, edges with three equivalent O(3)Sr2Eu2Cu2 octahedra, faces with two equivalent O(1)Sr4TaCu octahedra, and faces with four equivalent O(3)Sr2Eu2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-67°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sr2EuTa(CuO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.944
_cell_length_b   3.944
_cell_length_c   11.782
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   183.240
_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  0.200  1.0
  Sr  Sr1  1  0.500  0.500  0.800  1.0
  Eu  Eu2  1  0.500  0.500  0.500  1.0
  Ta  Ta3  1  0.000  0.000  0.000  1.0
  Cu  Cu4  1  0.000  0.000  0.356  1.0
  Cu  Cu5  1  0.000  0.000  0.644  1.0
  O  O6  1  0.000  0.000  0.168  1.0
  O  O7  1  0.000  0.000  0.832  1.0
  O  O8  1  0.000  0.500  0.000  1.0
  O  O9  1  0.500  0.000  0.000  1.0
  O  O10  1  0.000  0.500  0.367  1.0
  O  O11  1  0.000  0.500  0.633  1.0
  O  O12  1  0.500  0.000  0.367  1.0
  O  O13  1  0.500  0.000  0.633  1.0
[/CIF]
.