The material described by BaSrTa2O7 crystallizes in the orthorhombic Immm space group. Ba(1) is bonded in a 7-coordinate geometry to one O(5) and six equivalent O(3) atoms. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to four equivalent O(2), four equivalent O(4), and four equivalent O(5) atoms to form distorted SrO12 cuboctahedra that share corners with four equivalent Sr(2)O12 cuboctahedra, faces with two equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra, and faces with eight equivalent Ta(1)O6 octahedra. In the second Sr site, Sr(2) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(4) atoms to form distorted SrO12 cuboctahedra that share corners with four equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra, and faces with eight equivalent Ta(1)O6 octahedra. Ta(1) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(2) atoms to form TaO6 octahedra that share corners with five equivalent Ta(1)O6 octahedra, faces with two equivalent Sr(1)O12 cuboctahedra, and faces with two equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 12-27°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Sr(2) and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Sr(1), one Sr(2), and two equivalent Ta(1) atoms. In the third O site, O(3) is bonded to three equivalent Ba(1) and one Ta(1) atom to form a mixture of distorted corner and edge-sharing OBa3Ta tetrahedra. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Ta(1) atoms. In the fifth O site, O(5) is bonded in a distorted linear geometry to one Ba(1), two equivalent Sr(1), and two equivalent Ta(1) atoms. is represented by the CIF card [CIF]
data_BaSrTa2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.183
_cell_length_b   11.183
_cell_length_c   11.183
_cell_angle_alpha   159.240
_cell_angle_beta   138.586
_cell_angle_gamma   46.763
_symmetry_Int_Tables_number   1
_cell_volume   327.094
_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
  Ba  Ba0  1  0.238  0.738  0.500  1.0
  Ba  Ba1  1  0.762  0.262  0.500  1.0
  Sr  Sr2  1  0.500  0.500  0.000  1.0
  Sr  Sr3  1  0.000  0.500  0.500  1.0
  Ta  Ta4  1  0.854  0.103  0.752  1.0
  Ta  Ta5  1  0.351  0.103  0.248  1.0
  Ta  Ta6  1  0.146  0.897  0.248  1.0
  Ta  Ta7  1  0.649  0.897  0.752  1.0
  O  O8  1  0.920  0.920  0.000  1.0
  O  O9  1  0.155  0.407  0.747  1.0
  O  O10  1  0.340  0.593  0.747  1.0
  O  O11  1  0.011  0.807  0.203  1.0
  O  O12  1  0.713  0.000  0.713  1.0
  O  O13  1  0.660  0.407  0.253  1.0
  O  O14  1  0.396  0.193  0.203  1.0
  O  O15  1  0.287  0.000  0.287  1.0
  O  O16  1  0.989  0.193  0.797  1.0
  O  O17  1  0.387  0.887  0.500  1.0
  O  O18  1  0.080  0.080  0.000  1.0
  O  O19  1  0.845  0.593  0.253  1.0
  O  O20  1  0.604  0.807  0.797  1.0
  O  O21  1  0.613  0.113  0.500  1.0
[/CIF]
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The material described by BaSrTa2O7 crystallizes in the orthorhombic Immm space group. Ba(1) is bonded in a 7-coordinate geometry to one O(5) and six equivalent O(3) atoms. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to four equivalent O(2), four equivalent O(4), and four equivalent O(5) atoms to form distorted SrO12 cuboctahedra that share corners with four equivalent Sr(2)O12 cuboctahedra, faces with two equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra, and faces with eight equivalent Ta(1)O6 octahedra. In the second Sr site, Sr(2) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(4) atoms to form distorted SrO12 cuboctahedra that share corners with four equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra, and faces with eight equivalent Ta(1)O6 octahedra. Ta(1) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(2) atoms to form TaO6 octahedra that share corners with five equivalent Ta(1)O6 octahedra, faces with two equivalent Sr(1)O12 cuboctahedra, and faces with two equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 12-27°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Sr(2) and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Sr(1), one Sr(2), and two equivalent Ta(1) atoms. In the third O site, O(3) is bonded to three equivalent Ba(1) and one Ta(1) atom to form a mixture of distorted corner and edge-sharing OBa3Ta tetrahedra. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Ta(1) atoms. In the fifth O site, O(5) is bonded in a distorted linear geometry to one Ba(1), two equivalent Sr(1), and two equivalent Ta(1) atoms. is represented by the CIF card [CIF]
data_BaSrTa2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.183
_cell_length_b   11.183
_cell_length_c   11.183
_cell_angle_alpha   159.240
_cell_angle_beta   138.586
_cell_angle_gamma   46.763
_symmetry_Int_Tables_number   1
_cell_volume   327.094
_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
  Ba  Ba0  1  0.238  0.738  0.500  1.0
  Ba  Ba1  1  0.762  0.262  0.500  1.0
  Sr  Sr2  1  0.500  0.500  0.000  1.0
  Sr  Sr3  1  0.000  0.500  0.500  1.0
  Ta  Ta4  1  0.854  0.103  0.752  1.0
  Ta  Ta5  1  0.351  0.103  0.248  1.0
  Ta  Ta6  1  0.146  0.897  0.248  1.0
  Ta  Ta7  1  0.649  0.897  0.752  1.0
  O  O8  1  0.920  0.920  0.000  1.0
  O  O9  1  0.155  0.407  0.747  1.0
  O  O10  1  0.340  0.593  0.747  1.0
  O  O11  1  0.011  0.807  0.203  1.0
  O  O12  1  0.713  0.000  0.713  1.0
  O  O13  1  0.660  0.407  0.253  1.0
  O  O14  1  0.396  0.193  0.203  1.0
  O  O15  1  0.287  0.000  0.287  1.0
  O  O16  1  0.989  0.193  0.797  1.0
  O  O17  1  0.387  0.887  0.500  1.0
  O  O18  1  0.080  0.080  0.000  1.0
  O  O19  1  0.845  0.593  0.253  1.0
  O  O20  1  0.604  0.807  0.797  1.0
  O  O21  1  0.613  0.113  0.500  1.0
[/CIF]
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