The crystal structure described by Pr9O16 crystallizes in the triclinic P-1 space group. There are five inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a body-centered cubic geometry to one O(2), one O(3), one O(5), one O(6), one O(7), one O(8), and two equivalent O(4) atoms. In the second Pr site, Pr(2) is bonded to one O(1), one O(2), one O(3), two equivalent O(7), and two equivalent O(8) atoms to form distorted PrO7 hexagonal pyramids that share  a cornercorner with one Pr(4)O6 octahedra,  a cornercorner with one Pr(5)O7 pentagonal bipyramid, edges with two equivalent Pr(2)O7 hexagonal pyramids,  an edgeedge with one Pr(4)O6 octahedra, and edges with two equivalent Pr(5)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 58°. In the third Pr site, Pr(3) is bonded in a 7-coordinate geometry to one O(2), one O(4), one O(6), two equivalent O(3), and two equivalent O(5) atoms. In the fourth Pr site, Pr(4) is bonded to two equivalent O(1), two equivalent O(6), and two equivalent O(7) atoms to form a mixture of distorted edge and corner-sharing PrO6 octahedra. In the fifth Pr site, Pr(5) is bonded to one O(2), one O(4), one O(5), one O(6), one O(8), and two equivalent O(1) atoms to form distorted PrO7 pentagonal bipyramids that share  a cornercorner with one Pr(2)O7 hexagonal pyramid,  a cornercorner with one Pr(4)O6 octahedra, edges with two equivalent Pr(2)O7 hexagonal pyramids,  an edgeedge with one Pr(4)O6 octahedra, and  an edgeedge with one Pr(5)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 51°. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Pr(2), one Pr(4), and two equivalent Pr(5) atoms to form a mixture of edge and corner-sharing OPr4 tetrahedra. In the second O site, O(2) is bonded to one Pr(1), one Pr(2), one Pr(3), and one Pr(5) atom to form a mixture of edge and corner-sharing OPr4 tetrahedra. In the third O site, O(3) is bonded to one Pr(1), one Pr(2), and two equivalent Pr(3) atoms to form a mixture of edge and corner-sharing OPr4 tetrahedra. In the fourth O site, O(4) is bonded to one Pr(3), one Pr(5), and two equivalent Pr(1) atoms to form a mixture of edge and corner-sharing OPr4 tetrahedra. In the fifth O site, O(5) is bonded to one Pr(1), one Pr(5), and two equivalent Pr(3) atoms to form a mixture of edge and corner-sharing OPr4 tetrahedra. In the sixth O site, O(6) is bonded to one Pr(1), one Pr(3), one Pr(4), and one Pr(5) atom to form a mixture of edge and corner-sharing OPr4 tetrahedra. In the seventh O site, O(7) is bonded to one Pr(1), one Pr(4), and two equivalent Pr(2) atoms to form a mixture of edge and corner-sharing OPr4 tetrahedra. In the eighth O site, O(8) is bonded to one Pr(1), one Pr(5), and two equivalent Pr(2) atoms to form a mixture of edge and corner-sharing OPr4 tetrahedra. is represented by the CIF card [CIF]
data_Pr9O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.884
_cell_length_b   7.011
_cell_length_c   9.148
_cell_angle_alpha   74.045
_cell_angle_beta   80.835
_cell_angle_gamma   81.394
_symmetry_Int_Tables_number   1
_cell_volume   416.461
_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
  Pr  Pr0  1  0.672  0.309  0.672  1.0
  Pr  Pr1  1  0.328  0.691  0.328  1.0
  Pr  Pr2  1  0.409  0.238  0.101  1.0
  Pr  Pr3  1  0.230  0.124  0.527  1.0
  Pr  Pr4  1  0.000  0.000  0.000  1.0
  Pr  Pr5  1  0.107  0.521  0.773  1.0
  Pr  Pr6  1  0.893  0.479  0.227  1.0
  Pr  Pr7  1  0.591  0.762  0.899  1.0
  Pr  Pr8  1  0.770  0.876  0.473  1.0
  O  O9  1  0.071  0.296  0.045  1.0
  O  O10  1  0.779  0.612  0.702  1.0
  O  O11  1  0.528  0.005  0.663  1.0
  O  O12  1  0.647  0.581  0.429  1.0
  O  O13  1  0.929  0.704  0.955  1.0
  O  O14  1  0.124  0.806  0.546  1.0
  O  O15  1  0.353  0.419  0.571  1.0
  O  O16  1  0.974  0.787  0.257  1.0
  O  O17  1  0.668  0.088  0.940  1.0
  O  O18  1  0.221  0.388  0.298  1.0
  O  O19  1  0.026  0.213  0.743  1.0
  O  O20  1  0.424  0.497  0.858  1.0
  O  O21  1  0.472  0.995  0.337  1.0
  O  O22  1  0.576  0.503  0.142  1.0
  O  O23  1  0.876  0.194  0.454  1.0
  O  O24  1  0.332  0.912  0.060  1.0
[/CIF]
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The crystal structure described by Pr9O16 crystallizes in the triclinic P-1 space group. There are five inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a body-centered cubic geometry to one O(2), one O(3), one O(5), one O(6), one O(7), one O(8), and two equivalent O(4) atoms. In the second Pr site, Pr(2) is bonded to one O(1), one O(2), one O(3), two equivalent O(7), and two equivalent O(8) atoms to form distorted PrO7 hexagonal pyramids that share  a cornercorner with one Pr(4)O6 octahedra,  a cornercorner with one Pr(5)O7 pentagonal bipyramid, edges with two equivalent Pr(2)O7 hexagonal pyramids,  an edgeedge with one Pr(4)O6 octahedra, and edges with two equivalent Pr(5)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 58°. In the third Pr site, Pr(3) is bonded in a 7-coordinate geometry to one O(2), one O(4), one O(6), two equivalent O(3), and two equivalent O(5) atoms. In the fourth Pr site, Pr(4) is bonded to two equivalent O(1), two equivalent O(6), and two equivalent O(7) atoms to form a mixture of distorted edge and corner-sharing PrO6 octahedra. In the fifth Pr site, Pr(5) is bonded to one O(2), one O(4), one O(5), one O(6), one O(8), and two equivalent O(1) atoms to form distorted PrO7 pentagonal bipyramids that share  a cornercorner with one Pr(2)O7 hexagonal pyramid,  a cornercorner with one Pr(4)O6 octahedra, edges with two equivalent Pr(2)O7 hexagonal pyramids,  an edgeedge with one Pr(4)O6 octahedra, and  an edgeedge with one Pr(5)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 51°. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Pr(2), one Pr(4), and two equivalent Pr(5) atoms to form a mixture of edge and corner-sharing OPr4 tetrahedra. In the second O site, O(2) is bonded to one Pr(1), one Pr(2), one Pr(3), and one Pr(5) atom to form a mixture of edge and corner-sharing OPr4 tetrahedra. In the third O site, O(3) is bonded to one Pr(1), one Pr(2), and two equivalent Pr(3) atoms to form a mixture of edge and corner-sharing OPr4 tetrahedra. In the fourth O site, O(4) is bonded to one Pr(3), one Pr(5), and two equivalent Pr(1) atoms to form a mixture of edge and corner-sharing OPr4 tetrahedra. In the fifth O site, O(5) is bonded to one Pr(1), one Pr(5), and two equivalent Pr(3) atoms to form a mixture of edge and corner-sharing OPr4 tetrahedra. In the sixth O site, O(6) is bonded to one Pr(1), one Pr(3), one Pr(4), and one Pr(5) atom to form a mixture of edge and corner-sharing OPr4 tetrahedra. In the seventh O site, O(7) is bonded to one Pr(1), one Pr(4), and two equivalent Pr(2) atoms to form a mixture of edge and corner-sharing OPr4 tetrahedra. In the eighth O site, O(8) is bonded to one Pr(1), one Pr(5), and two equivalent Pr(2) atoms to form a mixture of edge and corner-sharing OPr4 tetrahedra. is represented by the CIF card [CIF]
data_Pr9O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.884
_cell_length_b   7.011
_cell_length_c   9.148
_cell_angle_alpha   74.045
_cell_angle_beta   80.835
_cell_angle_gamma   81.394
_symmetry_Int_Tables_number   1
_cell_volume   416.461
_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
  Pr  Pr0  1  0.672  0.309  0.672  1.0
  Pr  Pr1  1  0.328  0.691  0.328  1.0
  Pr  Pr2  1  0.409  0.238  0.101  1.0
  Pr  Pr3  1  0.230  0.124  0.527  1.0
  Pr  Pr4  1  0.000  0.000  0.000  1.0
  Pr  Pr5  1  0.107  0.521  0.773  1.0
  Pr  Pr6  1  0.893  0.479  0.227  1.0
  Pr  Pr7  1  0.591  0.762  0.899  1.0
  Pr  Pr8  1  0.770  0.876  0.473  1.0
  O  O9  1  0.071  0.296  0.045  1.0
  O  O10  1  0.779  0.612  0.702  1.0
  O  O11  1  0.528  0.005  0.663  1.0
  O  O12  1  0.647  0.581  0.429  1.0
  O  O13  1  0.929  0.704  0.955  1.0
  O  O14  1  0.124  0.806  0.546  1.0
  O  O15  1  0.353  0.419  0.571  1.0
  O  O16  1  0.974  0.787  0.257  1.0
  O  O17  1  0.668  0.088  0.940  1.0
  O  O18  1  0.221  0.388  0.298  1.0
  O  O19  1  0.026  0.213  0.743  1.0
  O  O20  1  0.424  0.497  0.858  1.0
  O  O21  1  0.472  0.995  0.337  1.0
  O  O22  1  0.576  0.503  0.142  1.0
  O  O23  1  0.876  0.194  0.454  1.0
  O  O24  1  0.332  0.912  0.060  1.0
[/CIF]
.