The material structure described by Be4Pr9O20 crystallizes in the triclinic P1 space group. There are four inequivalent Be sites. In the first Be site, Be(1) is bonded in a tetrahedral geometry to one O(2), one O(20), one O(6), and one O(7) atom. In the second Be site, Be(2) is bonded in a tetrahedral geometry to one O(11), one O(4), one O(5), and one O(9) atom. In the third Be site, Be(3) is bonded in a tetrahedral geometry to one O(10), one O(12), one O(16), and one O(17) atom. In the fourth Be site, Be(4) is bonded in a tetrahedral geometry to one O(1), one O(14), one O(15), and one O(19) atom. There are nine inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 9-coordinate geometry to one O(1), one O(14), one O(18), one O(19), one O(20), one O(5), one O(6), one O(8), and one O(9) atom. In the second Pr site, Pr(2) is bonded in a 8-coordinate geometry to one O(10), one O(16), one O(17), one O(19), one O(3), one O(4), one O(5), and one O(8) atom. In the third Pr site, Pr(3) is bonded in a 8-coordinate geometry to one O(1), one O(12), one O(14), one O(15), one O(3), one O(6), one O(7), and one O(8) atom. In the fourth Pr site, Pr(4) is bonded in a 9-coordinate geometry to one O(10), one O(11), one O(12), one O(13), one O(17), one O(2), one O(3), one O(5), and one O(6) atom. In the fifth Pr site, Pr(5) is bonded in a 9-coordinate geometry to one O(10), one O(11), one O(15), one O(16), one O(18), one O(19), one O(4), one O(8), and one O(9) atom. In the sixth Pr site, Pr(6) is bonded in a 8-coordinate geometry to one O(13), one O(14), one O(15), one O(18), one O(20), one O(6), one O(7), and one O(9) atom. In the seventh Pr site, Pr(7) is bonded in a 8-coordinate geometry to one O(11), one O(13), one O(16), one O(17), one O(18), one O(2), one O(4), and one O(5) atom. In the eighth Pr site, Pr(8) is bonded in a 8-coordinate geometry to one O(1), one O(12), one O(13), one O(14), one O(17), one O(2), one O(20), and one O(3) atom. In the ninth Pr site, Pr(9) is bonded in a 9-coordinate geometry to one O(1), one O(12), one O(13), one O(15), one O(16), one O(2), one O(20), one O(3), and one O(7) atom. There are twenty inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Be(4), one Pr(1), one Pr(3), one Pr(8), and one Pr(9) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Be(1), one Pr(4), one Pr(7), one Pr(8), and one Pr(9) atom. In the third O site, O(3) is bonded to one Pr(2), one Pr(3), one Pr(4), one Pr(8), and one Pr(9) atom to form distorted corner-sharing OPr5 trigonal bipyramids. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Be(2), one Pr(2), one Pr(5), and one Pr(7) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Be(2), one Pr(1), one Pr(2), one Pr(4), and one Pr(7) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Be(1), one Pr(1), one Pr(3), one Pr(4), and one Pr(6) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Be(1), one Pr(3), one Pr(6), and one Pr(9) atom. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Pr(1), one Pr(2), one Pr(3), and one Pr(5) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Be(2), one Pr(1), one Pr(5), and one Pr(6) atom. In the tenth O site, O(10) is bonded in a distorted single-bond geometry to one Be(3), one Pr(2), one Pr(4), and one Pr(5) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Be(2), one Pr(4), one Pr(5), and one Pr(7) atom. In the twelfth O site, O(12) is bonded in a 1-coordinate geometry to one Be(3), one Pr(3), one Pr(4), one Pr(8), and one Pr(9) atom. In the thirteenth O site, O(13) is bonded to one Pr(4), one Pr(6), one Pr(7), one Pr(8), and one Pr(9) atom to form distorted corner-sharing OPr5 square pyramids. In the fourteenth O site, O(14) is bonded in a 1-coordinate geometry to one Be(4), one Pr(1), one Pr(3), one Pr(6), and one Pr(8) atom. In the fifteenth O site, O(15) is bonded in a 1-coordinate geometry to one Be(4), one Pr(3), one Pr(5), one Pr(6), and one Pr(9) atom. In the sixteenth O site, O(16) is bonded in a 5-coordinate geometry to one Be(3), one Pr(2), one Pr(5), one Pr(7), and one Pr(9) atom. In the seventeenth O site, O(17) is bonded in a 1-coordinate geometry to one Be(3), one Pr(2), one Pr(4), one Pr(7), and one Pr(8) atom. In the eighteenth O site, O(18) is bonded in a rectangular see-saw-like geometry to one Pr(1), one Pr(5), one Pr(6), and one Pr(7) atom. In the nineteenth O site, O(19) is bonded in a 4-coordinate geometry to one Be(4), one Pr(1), one Pr(2), and one Pr(5) atom. In the twentieth O site, O(20) is bonded in a distorted single-bond geometry to one Be(1), one Pr(1), one Pr(6), one Pr(8), and one Pr(9) atom. is represented by the CIF card [CIF]
data_Pr9Be4O20
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.537
_cell_length_b   7.326
_cell_length_c   9.531
_cell_angle_alpha   89.993
_cell_angle_beta   89.454
_cell_angle_gamma   89.461
_symmetry_Int_Tables_number   1
_cell_volume   456.401
_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  0.930  0.807  0.822  1.0
  Pr  Pr1  1  0.897  0.509  0.531  1.0
  Pr  Pr2  1  0.603  0.501  0.033  1.0
  Pr  Pr3  1  0.574  0.814  0.342  1.0
  Pr  Pr4  1  0.423  0.316  0.667  1.0
  Pr  Pr5  1  0.412  0.006  0.957  1.0
  Pr  Pr6  1  0.099  0.010  0.480  1.0
  Pr  Pr7  1  0.085  0.737  0.173  1.0
  Pr  Pr8  1  0.079  0.274  0.167  1.0
  Be  Be9  1  0.807  0.004  0.105  1.0
  Be  Be10  1  0.672  0.004  0.611  1.0
  Be  Be11  1  0.314  0.502  0.386  1.0
  Be  Be12  1  0.180  0.504  0.896  1.0
  O  O13  1  0.977  0.512  0.999  1.0
  O  O14  1  0.876  0.992  0.273  1.0
  O  O15  1  0.828  0.543  0.275  1.0
  O  O16  1  0.782  0.201  0.577  1.0
  O  O17  1  0.818  0.833  0.569  1.0
  O  O18  1  0.694  0.822  0.058  1.0
  O  O19  1  0.708  0.196  0.075  1.0
  O  O20  1  0.691  0.537  0.772  1.0
  O  O21  1  0.652  0.038  0.775  1.0
  O  O22  1  0.526  0.525  0.475  1.0
  O  O23  1  0.458  0.018  0.530  1.0
  O  O24  1  0.347  0.509  0.217  1.0
  O  O25  1  0.321  0.994  0.217  1.0
  O  O26  1  0.286  0.703  0.944  1.0
  O  O27  1  0.328  0.328  0.928  1.0
  O  O28  1  0.176  0.327  0.436  1.0
  O  O29  1  0.193  0.702  0.418  1.0
  O  O30  1  0.199  0.032  0.726  1.0
  O  O31  1  0.122  0.528  0.730  1.0
  O  O32  1  0.028  0.011  0.014  1.0
[/CIF]
.
The material structure described by Be4Pr9O20 crystallizes in the triclinic P1 space group. There are four inequivalent Be sites. In the first Be site, Be(1) is bonded in a tetrahedral geometry to one O(2), one O(20), one O(6), and one O(7) atom. In the second Be site, Be(2) is bonded in a tetrahedral geometry to one O(11), one O(4), one O(5), and one O(9) atom. In the third Be site, Be(3) is bonded in a tetrahedral geometry to one O(10), one O(12), one O(16), and one O(17) atom. In the fourth Be site, Be(4) is bonded in a tetrahedral geometry to one O(1), one O(14), one O(15), and one O(19) atom. There are nine inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 9-coordinate geometry to one O(1), one O(14), one O(18), one O(19), one O(20), one O(5), one O(6), one O(8), and one O(9) atom. In the second Pr site, Pr(2) is bonded in a 8-coordinate geometry to one O(10), one O(16), one O(17), one O(19), one O(3), one O(4), one O(5), and one O(8) atom. In the third Pr site, Pr(3) is bonded in a 8-coordinate geometry to one O(1), one O(12), one O(14), one O(15), one O(3), one O(6), one O(7), and one O(8) atom. In the fourth Pr site, Pr(4) is bonded in a 9-coordinate geometry to one O(10), one O(11), one O(12), one O(13), one O(17), one O(2), one O(3), one O(5), and one O(6) atom. In the fifth Pr site, Pr(5) is bonded in a 9-coordinate geometry to one O(10), one O(11), one O(15), one O(16), one O(18), one O(19), one O(4), one O(8), and one O(9) atom. In the sixth Pr site, Pr(6) is bonded in a 8-coordinate geometry to one O(13), one O(14), one O(15), one O(18), one O(20), one O(6), one O(7), and one O(9) atom. In the seventh Pr site, Pr(7) is bonded in a 8-coordinate geometry to one O(11), one O(13), one O(16), one O(17), one O(18), one O(2), one O(4), and one O(5) atom. In the eighth Pr site, Pr(8) is bonded in a 8-coordinate geometry to one O(1), one O(12), one O(13), one O(14), one O(17), one O(2), one O(20), and one O(3) atom. In the ninth Pr site, Pr(9) is bonded in a 9-coordinate geometry to one O(1), one O(12), one O(13), one O(15), one O(16), one O(2), one O(20), one O(3), and one O(7) atom. There are twenty inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Be(4), one Pr(1), one Pr(3), one Pr(8), and one Pr(9) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Be(1), one Pr(4), one Pr(7), one Pr(8), and one Pr(9) atom. In the third O site, O(3) is bonded to one Pr(2), one Pr(3), one Pr(4), one Pr(8), and one Pr(9) atom to form distorted corner-sharing OPr5 trigonal bipyramids. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Be(2), one Pr(2), one Pr(5), and one Pr(7) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Be(2), one Pr(1), one Pr(2), one Pr(4), and one Pr(7) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Be(1), one Pr(1), one Pr(3), one Pr(4), and one Pr(6) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Be(1), one Pr(3), one Pr(6), and one Pr(9) atom. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Pr(1), one Pr(2), one Pr(3), and one Pr(5) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Be(2), one Pr(1), one Pr(5), and one Pr(6) atom. In the tenth O site, O(10) is bonded in a distorted single-bond geometry to one Be(3), one Pr(2), one Pr(4), and one Pr(5) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Be(2), one Pr(4), one Pr(5), and one Pr(7) atom. In the twelfth O site, O(12) is bonded in a 1-coordinate geometry to one Be(3), one Pr(3), one Pr(4), one Pr(8), and one Pr(9) atom. In the thirteenth O site, O(13) is bonded to one Pr(4), one Pr(6), one Pr(7), one Pr(8), and one Pr(9) atom to form distorted corner-sharing OPr5 square pyramids. In the fourteenth O site, O(14) is bonded in a 1-coordinate geometry to one Be(4), one Pr(1), one Pr(3), one Pr(6), and one Pr(8) atom. In the fifteenth O site, O(15) is bonded in a 1-coordinate geometry to one Be(4), one Pr(3), one Pr(5), one Pr(6), and one Pr(9) atom. In the sixteenth O site, O(16) is bonded in a 5-coordinate geometry to one Be(3), one Pr(2), one Pr(5), one Pr(7), and one Pr(9) atom. In the seventeenth O site, O(17) is bonded in a 1-coordinate geometry to one Be(3), one Pr(2), one Pr(4), one Pr(7), and one Pr(8) atom. In the eighteenth O site, O(18) is bonded in a rectangular see-saw-like geometry to one Pr(1), one Pr(5), one Pr(6), and one Pr(7) atom. In the nineteenth O site, O(19) is bonded in a 4-coordinate geometry to one Be(4), one Pr(1), one Pr(2), and one Pr(5) atom. In the twentieth O site, O(20) is bonded in a distorted single-bond geometry to one Be(1), one Pr(1), one Pr(6), one Pr(8), and one Pr(9) atom. is represented by the CIF card [CIF]
data_Pr9Be4O20
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.537
_cell_length_b   7.326
_cell_length_c   9.531
_cell_angle_alpha   89.993
_cell_angle_beta   89.454
_cell_angle_gamma   89.461
_symmetry_Int_Tables_number   1
_cell_volume   456.401
_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  0.930  0.807  0.822  1.0
  Pr  Pr1  1  0.897  0.509  0.531  1.0
  Pr  Pr2  1  0.603  0.501  0.033  1.0
  Pr  Pr3  1  0.574  0.814  0.342  1.0
  Pr  Pr4  1  0.423  0.316  0.667  1.0
  Pr  Pr5  1  0.412  0.006  0.957  1.0
  Pr  Pr6  1  0.099  0.010  0.480  1.0
  Pr  Pr7  1  0.085  0.737  0.173  1.0
  Pr  Pr8  1  0.079  0.274  0.167  1.0
  Be  Be9  1  0.807  0.004  0.105  1.0
  Be  Be10  1  0.672  0.004  0.611  1.0
  Be  Be11  1  0.314  0.502  0.386  1.0
  Be  Be12  1  0.180  0.504  0.896  1.0
  O  O13  1  0.977  0.512  0.999  1.0
  O  O14  1  0.876  0.992  0.273  1.0
  O  O15  1  0.828  0.543  0.275  1.0
  O  O16  1  0.782  0.201  0.577  1.0
  O  O17  1  0.818  0.833  0.569  1.0
  O  O18  1  0.694  0.822  0.058  1.0
  O  O19  1  0.708  0.196  0.075  1.0
  O  O20  1  0.691  0.537  0.772  1.0
  O  O21  1  0.652  0.038  0.775  1.0
  O  O22  1  0.526  0.525  0.475  1.0
  O  O23  1  0.458  0.018  0.530  1.0
  O  O24  1  0.347  0.509  0.217  1.0
  O  O25  1  0.321  0.994  0.217  1.0
  O  O26  1  0.286  0.703  0.944  1.0
  O  O27  1  0.328  0.328  0.928  1.0
  O  O28  1  0.176  0.327  0.436  1.0
  O  O29  1  0.193  0.702  0.418  1.0
  O  O30  1  0.199  0.032  0.726  1.0
  O  O31  1  0.122  0.528  0.730  1.0
  O  O32  1  0.028  0.011  0.014  1.0
[/CIF]
.