The material structure described by Ca2Hf7O16 crystallizes in the trigonal R-3 space group. There are six inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a body-centered cubic geometry to one O(3), one O(4), and six equivalent O(2) atoms. In the second Ca site, Ca(1) is bonded in a body-centered cubic geometry to one O(3), one O(4), and six equivalent O(2) atoms. In the third Ca site, Ca(1) is bonded in a body-centered cubic geometry to one O(3), one O(4), and six equivalent O(2) atoms. In the fourth Ca site, Ca(1) is bonded in a body-centered cubic geometry to one O(3), one O(4), and six equivalent O(2) atoms. In the fifth Ca site, Ca(1) is bonded in a body-centered cubic geometry to one O(3), one O(4), and six equivalent O(2) atoms. In the sixth Ca site, Ca(1) is bonded in a body-centered cubic geometry to one O(3), one O(4), and six equivalent O(2) atoms. There are nine inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to one O(2), one O(3), one O(4), and four equivalent O(1) atoms to form distorted HfO7 pentagonal bipyramids that share  a cornercorner with one Hf(2)O6 octahedra; corners with two equivalent Hf(1)O7 pentagonal bipyramids; and edges with seven Hf(1,1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. In the second Hf site, Hf(1) is bonded to one O(2), one O(3), one O(4), and four equivalent O(1) atoms to form distorted HfO7 pentagonal bipyramids that share  a cornercorner with one Hf(2)O6 octahedra; corners with two equivalent Hf(1)O7 pentagonal bipyramids; and edges with seven Hf(1,1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. In the third Hf site, Hf(2) is bonded to six equivalent O(2) atoms to form corner-sharing HfO6 octahedra. In the fourth Hf site, Hf(1) is bonded to one O(2), one O(3), one O(4), and four equivalent O(1) atoms to form distorted HfO7 pentagonal bipyramids that share  a cornercorner with one Hf(2)O6 octahedra; corners with two equivalent Hf(1)O7 pentagonal bipyramids; and edges with seven Hf(1,1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. In the fifth Hf site, Hf(1) is bonded to one O(2), one O(3), one O(4), and four equivalent O(1) atoms to form distorted HfO7 pentagonal bipyramids that share  a cornercorner with one Hf(2)O6 octahedra; corners with two equivalent Hf(1)O7 pentagonal bipyramids; and edges with seven Hf(1,1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. In the sixth Hf site, Hf(2) is bonded to six equivalent O(2) atoms to form corner-sharing HfO6 octahedra. In the seventh Hf site, Hf(1) is bonded to one O(2), one O(3), one O(4), and four equivalent O(1) atoms to form distorted HfO7 pentagonal bipyramids that share  a cornercorner with one Hf(2)O6 octahedra; corners with two equivalent Hf(1)O7 pentagonal bipyramids; and edges with seven Hf(1,1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. In the eighth Hf site, Hf(1) is bonded to one O(2), one O(3), one O(4), and four equivalent O(1) atoms to form distorted HfO7 pentagonal bipyramids that share  a cornercorner with one Hf(2)O6 octahedra; corners with two equivalent Hf(1)O7 pentagonal bipyramids; and edges with seven Hf(1,1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. In the ninth Hf site, Hf(2) is bonded to six equivalent O(2) atoms to form corner-sharing HfO6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded to four Hf(1,1) atoms to form OHf4 tetrahedra that share corners with two equivalent O(3)CaHf3 tetrahedra, corners with two equivalent O(4)CaHf3 tetrahedra, corners with six equivalent O(1)Hf4 tetrahedra, corners with four equivalent O(2)Ca2Hf2 trigonal pyramids,  an edgeedge with one O(3)CaHf3 tetrahedra,  an edgeedge with one O(4)CaHf3 tetrahedra, and edges with three equivalent O(1)Hf4 tetrahedra. In the second O site, O(2) is bonded to two Ca(1,1); one Hf(1); and one Hf(2) atom to form distorted OCa2Hf2 trigonal pyramids that share  a cornercorner with one O(3)CaHf3 tetrahedra,  a cornercorner with one O(4)CaHf3 tetrahedra, corners with four equivalent O(1)Hf4 tetrahedra, corners with nine equivalent O(2)Ca2Hf2 trigonal pyramids,  an edgeedge with one O(3)CaHf3 tetrahedra,  an edgeedge with one O(4)CaHf3 tetrahedra, and edges with three equivalent O(2)Ca2Hf2 trigonal pyramids. In the third O site, O(3) is bonded to one Ca(1) and three equivalent Hf(1) atoms to form distorted OCaHf3 tetrahedra that share corners with four equivalent O(4)CaHf3 tetrahedra, corners with six equivalent O(1)Hf4 tetrahedra, corners with three equivalent O(2)Ca2Hf2 trigonal pyramids, edges with three equivalent O(1)Hf4 tetrahedra, and edges with three equivalent O(2)Ca2Hf2 trigonal pyramids. In the fourth O site, O(4) is bonded to one Ca(1) and three equivalent Hf(1) atoms to form OCaHf3 tetrahedra that share corners with four equivalent O(3)CaHf3 tetrahedra, corners with six equivalent O(1)Hf4 tetrahedra, corners with three equivalent O(2)Ca2Hf2 trigonal pyramids, edges with three equivalent O(1)Hf4 tetrahedra, and edges with three equivalent O(2)Ca2Hf2 trigonal pyramids. is represented by the CIF card [CIF]
data_Ca2Hf7O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.485
_cell_length_b   9.485
_cell_length_c   9.485
_cell_angle_alpha   38.796
_cell_angle_beta   38.796
_cell_angle_gamma   38.796
_symmetry_Int_Tables_number   1
_cell_volume   301.111
_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
  Ca  Ca0  1  0.333  0.333  0.333  1.0
  Ca  Ca1  1  0.667  0.667  0.667  1.0
  Hf  Hf2  1  0.486  0.744  0.113  1.0
  Hf  Hf3  1  0.744  0.113  0.486  1.0
  Hf  Hf4  1  0.113  0.486  0.744  1.0
  Hf  Hf5  1  0.514  0.256  0.887  1.0
  Hf  Hf6  1  0.256  0.887  0.514  1.0
  Hf  Hf7  1  0.887  0.514  0.256  1.0
  Hf  Hf8  1  0.000  0.000  0.000  1.0
  O  O9  1  0.590  0.850  0.151  1.0
  O  O10  1  0.850  0.151  0.590  1.0
  O  O11  1  0.151  0.590  0.850  1.0
  O  O12  1  0.410  0.150  0.849  1.0
  O  O13  1  0.150  0.849  0.410  1.0
  O  O14  1  0.849  0.410  0.150  1.0
  O  O15  1  0.328  0.761  0.033  1.0
  O  O16  1  0.761  0.033  0.328  1.0
  O  O17  1  0.033  0.328  0.761  1.0
  O  O18  1  0.762  0.762  0.762  1.0
  O  O19  1  0.238  0.238  0.238  1.0
  O  O20  1  0.573  0.573  0.573  1.0
  O  O21  1  0.427  0.427  0.427  1.0
  O  O22  1  0.967  0.672  0.239  1.0
  O  O23  1  0.239  0.967  0.672  1.0
  O  O24  1  0.672  0.239  0.967  1.0
[/CIF]
.
The material structure described by Ca2Hf7O16 crystallizes in the trigonal R-3 space group. There are six inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a body-centered cubic geometry to one O(3), one O(4), and six equivalent O(2) atoms. In the second Ca site, Ca(1) is bonded in a body-centered cubic geometry to one O(3), one O(4), and six equivalent O(2) atoms. In the third Ca site, Ca(1) is bonded in a body-centered cubic geometry to one O(3), one O(4), and six equivalent O(2) atoms. In the fourth Ca site, Ca(1) is bonded in a body-centered cubic geometry to one O(3), one O(4), and six equivalent O(2) atoms. In the fifth Ca site, Ca(1) is bonded in a body-centered cubic geometry to one O(3), one O(4), and six equivalent O(2) atoms. In the sixth Ca site, Ca(1) is bonded in a body-centered cubic geometry to one O(3), one O(4), and six equivalent O(2) atoms. There are nine inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to one O(2), one O(3), one O(4), and four equivalent O(1) atoms to form distorted HfO7 pentagonal bipyramids that share  a cornercorner with one Hf(2)O6 octahedra; corners with two equivalent Hf(1)O7 pentagonal bipyramids; and edges with seven Hf(1,1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. In the second Hf site, Hf(1) is bonded to one O(2), one O(3), one O(4), and four equivalent O(1) atoms to form distorted HfO7 pentagonal bipyramids that share  a cornercorner with one Hf(2)O6 octahedra; corners with two equivalent Hf(1)O7 pentagonal bipyramids; and edges with seven Hf(1,1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. In the third Hf site, Hf(2) is bonded to six equivalent O(2) atoms to form corner-sharing HfO6 octahedra. In the fourth Hf site, Hf(1) is bonded to one O(2), one O(3), one O(4), and four equivalent O(1) atoms to form distorted HfO7 pentagonal bipyramids that share  a cornercorner with one Hf(2)O6 octahedra; corners with two equivalent Hf(1)O7 pentagonal bipyramids; and edges with seven Hf(1,1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. In the fifth Hf site, Hf(1) is bonded to one O(2), one O(3), one O(4), and four equivalent O(1) atoms to form distorted HfO7 pentagonal bipyramids that share  a cornercorner with one Hf(2)O6 octahedra; corners with two equivalent Hf(1)O7 pentagonal bipyramids; and edges with seven Hf(1,1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. In the sixth Hf site, Hf(2) is bonded to six equivalent O(2) atoms to form corner-sharing HfO6 octahedra. In the seventh Hf site, Hf(1) is bonded to one O(2), one O(3), one O(4), and four equivalent O(1) atoms to form distorted HfO7 pentagonal bipyramids that share  a cornercorner with one Hf(2)O6 octahedra; corners with two equivalent Hf(1)O7 pentagonal bipyramids; and edges with seven Hf(1,1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. In the eighth Hf site, Hf(1) is bonded to one O(2), one O(3), one O(4), and four equivalent O(1) atoms to form distorted HfO7 pentagonal bipyramids that share  a cornercorner with one Hf(2)O6 octahedra; corners with two equivalent Hf(1)O7 pentagonal bipyramids; and edges with seven Hf(1,1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. In the ninth Hf site, Hf(2) is bonded to six equivalent O(2) atoms to form corner-sharing HfO6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded to four Hf(1,1) atoms to form OHf4 tetrahedra that share corners with two equivalent O(3)CaHf3 tetrahedra, corners with two equivalent O(4)CaHf3 tetrahedra, corners with six equivalent O(1)Hf4 tetrahedra, corners with four equivalent O(2)Ca2Hf2 trigonal pyramids,  an edgeedge with one O(3)CaHf3 tetrahedra,  an edgeedge with one O(4)CaHf3 tetrahedra, and edges with three equivalent O(1)Hf4 tetrahedra. In the second O site, O(2) is bonded to two Ca(1,1); one Hf(1); and one Hf(2) atom to form distorted OCa2Hf2 trigonal pyramids that share  a cornercorner with one O(3)CaHf3 tetrahedra,  a cornercorner with one O(4)CaHf3 tetrahedra, corners with four equivalent O(1)Hf4 tetrahedra, corners with nine equivalent O(2)Ca2Hf2 trigonal pyramids,  an edgeedge with one O(3)CaHf3 tetrahedra,  an edgeedge with one O(4)CaHf3 tetrahedra, and edges with three equivalent O(2)Ca2Hf2 trigonal pyramids. In the third O site, O(3) is bonded to one Ca(1) and three equivalent Hf(1) atoms to form distorted OCaHf3 tetrahedra that share corners with four equivalent O(4)CaHf3 tetrahedra, corners with six equivalent O(1)Hf4 tetrahedra, corners with three equivalent O(2)Ca2Hf2 trigonal pyramids, edges with three equivalent O(1)Hf4 tetrahedra, and edges with three equivalent O(2)Ca2Hf2 trigonal pyramids. In the fourth O site, O(4) is bonded to one Ca(1) and three equivalent Hf(1) atoms to form OCaHf3 tetrahedra that share corners with four equivalent O(3)CaHf3 tetrahedra, corners with six equivalent O(1)Hf4 tetrahedra, corners with three equivalent O(2)Ca2Hf2 trigonal pyramids, edges with three equivalent O(1)Hf4 tetrahedra, and edges with three equivalent O(2)Ca2Hf2 trigonal pyramids. is represented by the CIF card [CIF]
data_Ca2Hf7O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.485
_cell_length_b   9.485
_cell_length_c   9.485
_cell_angle_alpha   38.796
_cell_angle_beta   38.796
_cell_angle_gamma   38.796
_symmetry_Int_Tables_number   1
_cell_volume   301.111
_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
  Ca  Ca0  1  0.333  0.333  0.333  1.0
  Ca  Ca1  1  0.667  0.667  0.667  1.0
  Hf  Hf2  1  0.486  0.744  0.113  1.0
  Hf  Hf3  1  0.744  0.113  0.486  1.0
  Hf  Hf4  1  0.113  0.486  0.744  1.0
  Hf  Hf5  1  0.514  0.256  0.887  1.0
  Hf  Hf6  1  0.256  0.887  0.514  1.0
  Hf  Hf7  1  0.887  0.514  0.256  1.0
  Hf  Hf8  1  0.000  0.000  0.000  1.0
  O  O9  1  0.590  0.850  0.151  1.0
  O  O10  1  0.850  0.151  0.590  1.0
  O  O11  1  0.151  0.590  0.850  1.0
  O  O12  1  0.410  0.150  0.849  1.0
  O  O13  1  0.150  0.849  0.410  1.0
  O  O14  1  0.849  0.410  0.150  1.0
  O  O15  1  0.328  0.761  0.033  1.0
  O  O16  1  0.761  0.033  0.328  1.0
  O  O17  1  0.033  0.328  0.761  1.0
  O  O18  1  0.762  0.762  0.762  1.0
  O  O19  1  0.238  0.238  0.238  1.0
  O  O20  1  0.573  0.573  0.573  1.0
  O  O21  1  0.427  0.427  0.427  1.0
  O  O22  1  0.967  0.672  0.239  1.0
  O  O23  1  0.239  0.967  0.672  1.0
  O  O24  1  0.672  0.239  0.967  1.0
[/CIF]
.