The compound described by Ba2Hf7O16 crystallizes in the trigonal R-3 space group. Ba(1) is bonded in a 8-coordinate geometry to one O(1), one O(4), and six equivalent O(2) atoms. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to six equivalent O(2) atoms to form corner-sharing HfO6 octahedra. In the second Hf site, Hf(2) is bonded to one O(1), one O(2), one O(4), and four equivalent O(3) atoms to form distorted HfO7 pentagonal bipyramids that share  a cornercorner with one Hf(1)O6 octahedra, corners with two equivalent Hf(2)O7 pentagonal bipyramids, and edges with seven equivalent Hf(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 35°. There are four inequivalent O sites. In the first O site, O(4) is bonded to one Ba(1) and three equivalent Hf(2) atoms to form distorted OBaHf3 tetrahedra that share corners with four equivalent O(1)BaHf3 tetrahedra, corners with six equivalent O(3)Hf4 tetrahedra, corners with three equivalent O(2)Ba2Hf2 trigonal pyramids, edges with three equivalent O(3)Hf4 tetrahedra, and edges with three equivalent O(2)Ba2Hf2 trigonal pyramids. In the second O site, O(1) is bonded to one Ba(1) and three equivalent Hf(2) atoms to form distorted OBaHf3 tetrahedra that share corners with four equivalent O(4)BaHf3 tetrahedra, corners with six equivalent O(3)Hf4 tetrahedra, corners with three equivalent O(2)Ba2Hf2 trigonal pyramids, edges with three equivalent O(3)Hf4 tetrahedra, and edges with three equivalent O(2)Ba2Hf2 trigonal pyramids. In the third O site, O(2) is bonded to two equivalent Ba(1), one Hf(1), and one Hf(2) atom to form distorted OBa2Hf2 trigonal pyramids that share  a cornercorner with one O(1)BaHf3 tetrahedra,  a cornercorner with one O(4)BaHf3 tetrahedra, corners with four equivalent O(3)Hf4 tetrahedra, corners with nine equivalent O(2)Ba2Hf2 trigonal pyramids,  an edgeedge with one O(1)BaHf3 tetrahedra,  an edgeedge with one O(4)BaHf3 tetrahedra, and edges with three equivalent O(2)Ba2Hf2 trigonal pyramids. In the fourth O site, O(3) is bonded to four equivalent Hf(2) atoms to form distorted OHf4 tetrahedra that share corners with two equivalent O(1)BaHf3 tetrahedra, corners with two equivalent O(4)BaHf3 tetrahedra, corners with six equivalent O(3)Hf4 tetrahedra, corners with four equivalent O(2)Ba2Hf2 trigonal pyramids,  an edgeedge with one O(1)BaHf3 tetrahedra,  an edgeedge with one O(4)BaHf3 tetrahedra, and edges with three equivalent O(3)Hf4 tetrahedra. is represented by the CIF card [CIF]
data_Ba2Hf7O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.778
_cell_length_b   9.778
_cell_length_c   9.778
_cell_angle_alpha   38.624
_cell_angle_beta   38.624
_cell_angle_gamma   38.624
_symmetry_Int_Tables_number   1
_cell_volume   327.352
_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
  Ba  Ba0  1  0.334  0.334  0.334  1.0
  Ba  Ba1  1  0.666  0.666  0.666  1.0
  Hf  Hf2  1  0.000  0.000  0.000  1.0
  Hf  Hf3  1  0.886  0.248  0.516  1.0
  Hf  Hf4  1  0.484  0.114  0.752  1.0
  Hf  Hf5  1  0.752  0.484  0.114  1.0
  Hf  Hf6  1  0.248  0.516  0.886  1.0
  Hf  Hf7  1  0.516  0.886  0.248  1.0
  Hf  Hf8  1  0.114  0.752  0.484  1.0
  O  O9  1  0.233  0.233  0.233  1.0
  O  O10  1  0.961  0.216  0.687  1.0
  O  O11  1  0.851  0.150  0.411  1.0
  O  O12  1  0.589  0.149  0.850  1.0
  O  O13  1  0.313  0.039  0.784  1.0
  O  O14  1  0.784  0.313  0.039  1.0
  O  O15  1  0.850  0.589  0.149  1.0
  O  O16  1  0.433  0.433  0.433  1.0
  O  O17  1  0.567  0.567  0.567  1.0
  O  O18  1  0.150  0.411  0.851  1.0
  O  O19  1  0.216  0.687  0.961  1.0
  O  O20  1  0.687  0.961  0.216  1.0
  O  O21  1  0.411  0.851  0.150  1.0
  O  O22  1  0.149  0.850  0.589  1.0
  O  O23  1  0.039  0.784  0.313  1.0
  O  O24  1  0.767  0.767  0.767  1.0
[/CIF]
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The compound described by Ba2Hf7O16 crystallizes in the trigonal R-3 space group. Ba(1) is bonded in a 8-coordinate geometry to one O(1), one O(4), and six equivalent O(2) atoms. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to six equivalent O(2) atoms to form corner-sharing HfO6 octahedra. In the second Hf site, Hf(2) is bonded to one O(1), one O(2), one O(4), and four equivalent O(3) atoms to form distorted HfO7 pentagonal bipyramids that share  a cornercorner with one Hf(1)O6 octahedra, corners with two equivalent Hf(2)O7 pentagonal bipyramids, and edges with seven equivalent Hf(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 35°. There are four inequivalent O sites. In the first O site, O(4) is bonded to one Ba(1) and three equivalent Hf(2) atoms to form distorted OBaHf3 tetrahedra that share corners with four equivalent O(1)BaHf3 tetrahedra, corners with six equivalent O(3)Hf4 tetrahedra, corners with three equivalent O(2)Ba2Hf2 trigonal pyramids, edges with three equivalent O(3)Hf4 tetrahedra, and edges with three equivalent O(2)Ba2Hf2 trigonal pyramids. In the second O site, O(1) is bonded to one Ba(1) and three equivalent Hf(2) atoms to form distorted OBaHf3 tetrahedra that share corners with four equivalent O(4)BaHf3 tetrahedra, corners with six equivalent O(3)Hf4 tetrahedra, corners with three equivalent O(2)Ba2Hf2 trigonal pyramids, edges with three equivalent O(3)Hf4 tetrahedra, and edges with three equivalent O(2)Ba2Hf2 trigonal pyramids. In the third O site, O(2) is bonded to two equivalent Ba(1), one Hf(1), and one Hf(2) atom to form distorted OBa2Hf2 trigonal pyramids that share  a cornercorner with one O(1)BaHf3 tetrahedra,  a cornercorner with one O(4)BaHf3 tetrahedra, corners with four equivalent O(3)Hf4 tetrahedra, corners with nine equivalent O(2)Ba2Hf2 trigonal pyramids,  an edgeedge with one O(1)BaHf3 tetrahedra,  an edgeedge with one O(4)BaHf3 tetrahedra, and edges with three equivalent O(2)Ba2Hf2 trigonal pyramids. In the fourth O site, O(3) is bonded to four equivalent Hf(2) atoms to form distorted OHf4 tetrahedra that share corners with two equivalent O(1)BaHf3 tetrahedra, corners with two equivalent O(4)BaHf3 tetrahedra, corners with six equivalent O(3)Hf4 tetrahedra, corners with four equivalent O(2)Ba2Hf2 trigonal pyramids,  an edgeedge with one O(1)BaHf3 tetrahedra,  an edgeedge with one O(4)BaHf3 tetrahedra, and edges with three equivalent O(3)Hf4 tetrahedra. is represented by the CIF card [CIF]
data_Ba2Hf7O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.778
_cell_length_b   9.778
_cell_length_c   9.778
_cell_angle_alpha   38.624
_cell_angle_beta   38.624
_cell_angle_gamma   38.624
_symmetry_Int_Tables_number   1
_cell_volume   327.352
_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
  Ba  Ba0  1  0.334  0.334  0.334  1.0
  Ba  Ba1  1  0.666  0.666  0.666  1.0
  Hf  Hf2  1  0.000  0.000  0.000  1.0
  Hf  Hf3  1  0.886  0.248  0.516  1.0
  Hf  Hf4  1  0.484  0.114  0.752  1.0
  Hf  Hf5  1  0.752  0.484  0.114  1.0
  Hf  Hf6  1  0.248  0.516  0.886  1.0
  Hf  Hf7  1  0.516  0.886  0.248  1.0
  Hf  Hf8  1  0.114  0.752  0.484  1.0
  O  O9  1  0.233  0.233  0.233  1.0
  O  O10  1  0.961  0.216  0.687  1.0
  O  O11  1  0.851  0.150  0.411  1.0
  O  O12  1  0.589  0.149  0.850  1.0
  O  O13  1  0.313  0.039  0.784  1.0
  O  O14  1  0.784  0.313  0.039  1.0
  O  O15  1  0.850  0.589  0.149  1.0
  O  O16  1  0.433  0.433  0.433  1.0
  O  O17  1  0.567  0.567  0.567  1.0
  O  O18  1  0.150  0.411  0.851  1.0
  O  O19  1  0.216  0.687  0.961  1.0
  O  O20  1  0.687  0.961  0.216  1.0
  O  O21  1  0.411  0.851  0.150  1.0
  O  O22  1  0.149  0.850  0.589  1.0
  O  O23  1  0.039  0.784  0.313  1.0
  O  O24  1  0.767  0.767  0.767  1.0
[/CIF]
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