The material described by Li2SrTa2O7 crystallizes in the tetragonal I4/mmm space group. Li(1) is bonded in a 4-coordinate geometry to four equivalent O(3) atoms. Sr(1) is bonded to four equivalent O(1) and eight equivalent O(2) atoms to form SrO12 cuboctahedra that share corners with four equivalent Sr(1)O12 cuboctahedra, faces with four equivalent Sr(1)O12 cuboctahedra, and faces with eight equivalent Ta(1)O6 octahedra. Ta(1) is bonded to one O(1), one O(3), and four equivalent O(2) atoms to form TaO6 octahedra that share corners with five equivalent Ta(1)O6 octahedra and faces with four equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-11°. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Sr(1) and two equivalent Ta(1) atoms to form distorted OSr4Ta2 octahedra that share corners with four equivalent O(1)Sr4Ta2 octahedra, corners with two equivalent O(3)Li4Ta trigonal bipyramids, and edges with four equivalent O(1)Sr4Ta2 octahedra. The corner-sharing octahedra are not tilted. In the second O site, O(2) is bonded in a distorted linear geometry to two equivalent Sr(1) and two equivalent Ta(1) atoms. In the third O site, O(3) is bonded to four equivalent Li(1) and one Ta(1) atom to form distorted OLi4Ta trigonal bipyramids that share  a cornercorner with one O(1)Sr4Ta2 octahedra, corners with four equivalent O(3)Li4Ta trigonal bipyramids, and edges with four equivalent O(3)Li4Ta trigonal bipyramids. The corner-sharing octahedra are not tilted. is represented by the CIF file [CIF]
data_SrLi2Ta2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.941
_cell_length_b   3.941
_cell_length_c   9.450
_cell_angle_alpha   102.035
_cell_angle_beta   102.035
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   140.223
_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  0.000  0.000  0.000  1.0
  Li  Li1  1  0.250  0.750  0.500  1.0
  Li  Li2  1  0.750  0.250  0.500  1.0
  Ta  Ta3  1  0.616  0.616  0.232  1.0
  Ta  Ta4  1  0.384  0.384  0.768  1.0
  O  O5  1  0.500  0.500  0.000  1.0
  O  O6  1  0.605  0.105  0.211  1.0
  O  O7  1  0.105  0.605  0.211  1.0
  O  O8  1  0.395  0.895  0.789  1.0
  O  O9  1  0.895  0.395  0.789  1.0
  O  O10  1  0.280  0.280  0.561  1.0
  O  O11  1  0.720  0.720  0.439  1.0
[/CIF]
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The material described by Li2SrTa2O7 crystallizes in the tetragonal I4/mmm space group. Li(1) is bonded in a 4-coordinate geometry to four equivalent O(3) atoms. Sr(1) is bonded to four equivalent O(1) and eight equivalent O(2) atoms to form SrO12 cuboctahedra that share corners with four equivalent Sr(1)O12 cuboctahedra, faces with four equivalent Sr(1)O12 cuboctahedra, and faces with eight equivalent Ta(1)O6 octahedra. Ta(1) is bonded to one O(1), one O(3), and four equivalent O(2) atoms to form TaO6 octahedra that share corners with five equivalent Ta(1)O6 octahedra and faces with four equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-11°. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Sr(1) and two equivalent Ta(1) atoms to form distorted OSr4Ta2 octahedra that share corners with four equivalent O(1)Sr4Ta2 octahedra, corners with two equivalent O(3)Li4Ta trigonal bipyramids, and edges with four equivalent O(1)Sr4Ta2 octahedra. The corner-sharing octahedra are not tilted. In the second O site, O(2) is bonded in a distorted linear geometry to two equivalent Sr(1) and two equivalent Ta(1) atoms. In the third O site, O(3) is bonded to four equivalent Li(1) and one Ta(1) atom to form distorted OLi4Ta trigonal bipyramids that share  a cornercorner with one O(1)Sr4Ta2 octahedra, corners with four equivalent O(3)Li4Ta trigonal bipyramids, and edges with four equivalent O(3)Li4Ta trigonal bipyramids. The corner-sharing octahedra are not tilted. is represented by the CIF file [CIF]
data_SrLi2Ta2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.941
_cell_length_b   3.941
_cell_length_c   9.450
_cell_angle_alpha   102.035
_cell_angle_beta   102.035
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   140.223
_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  0.000  0.000  0.000  1.0
  Li  Li1  1  0.250  0.750  0.500  1.0
  Li  Li2  1  0.750  0.250  0.500  1.0
  Ta  Ta3  1  0.616  0.616  0.232  1.0
  Ta  Ta4  1  0.384  0.384  0.768  1.0
  O  O5  1  0.500  0.500  0.000  1.0
  O  O6  1  0.605  0.105  0.211  1.0
  O  O7  1  0.105  0.605  0.211  1.0
  O  O8  1  0.395  0.895  0.789  1.0
  O  O9  1  0.895  0.395  0.789  1.0
  O  O10  1  0.280  0.280  0.561  1.0
  O  O11  1  0.720  0.720  0.439  1.0
[/CIF]
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