The compound described by Sr3Pr4O9 crystallizes in the triclinic P1 space group. There are six inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one O(11), one O(17), one O(5), one O(6), one O(8), and one O(9) atom to form distorted SrO6 pentagonal pyramids that share  a cornercorner with one Sr(6)O6 pentagonal pyramid,  an edgeedge with one Sr(6)O6 pentagonal pyramid,  an edgeedge with one Pr(3)O6 pentagonal pyramid,  an edgeedge with one Pr(6)O6 pentagonal pyramid, and  a faceface with one Pr(2)O6 pentagonal pyramid. In the second Sr site, Sr(2) is bonded in a 6-coordinate geometry to one O(10), one O(12), one O(2), one O(3), one O(4), and one O(9) atom. In the third Sr site, Sr(3) is bonded in a 6-coordinate geometry to one O(10), one O(11), one O(14), one O(4), one O(6), and one O(8) atom. In the fourth Sr site, Sr(4) is bonded in a 6-coordinate geometry to one O(12), one O(13), one O(16), one O(18), one O(4), and one O(7) atom. In the fifth Sr site, Sr(5) is bonded in a 5-coordinate geometry to one O(13), one O(14), one O(15), one O(17), and one O(18) atom. In the sixth Sr site, Sr(6) is bonded to one O(14), one O(16), one O(17), one O(18), one O(5), and one O(6) atom to form distorted SrO6 pentagonal pyramids that share  a cornercorner with one Sr(1)O6 pentagonal pyramid,  a cornercorner with one Pr(2)O6 pentagonal pyramid, corners with two equivalent Pr(1)O5 tetrahedra,  an edgeedge with one Sr(1)O6 pentagonal pyramid,  an edgeedge with one Pr(3)O6 pentagonal pyramid, and  an edgeedge with one Pr(6)O6 pentagonal pyramid. There are eight inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to one O(1), one O(14), one O(15), one O(16), and one O(4) atom to form distorted PrO5 tetrahedra that share  a cornercorner with one Pr(3)O6 pentagonal pyramid,  a cornercorner with one Pr(6)O6 pentagonal pyramid, corners with two equivalent Sr(6)O6 pentagonal pyramids, and  an edgeedge with one Pr(3)O6 pentagonal pyramid. In the second Pr site, Pr(2) is bonded to one O(17), one O(2), one O(3), one O(7), one O(8), and one O(9) atom to form distorted PrO6 pentagonal pyramids that share  a cornercorner with one Sr(6)O6 pentagonal pyramid,  an edgeedge with one Pr(6)O6 pentagonal pyramid, and  a faceface with one Sr(1)O6 pentagonal pyramid. In the third Pr site, Pr(3) is bonded to one O(1), one O(11), one O(12), one O(16), one O(4), and one O(5) atom to form distorted PrO6 pentagonal pyramids that share corners with two equivalent Pr(6)O6 pentagonal pyramids,  a cornercorner with one Pr(1)O5 tetrahedra,  an edgeedge with one Sr(1)O6 pentagonal pyramid,  an edgeedge with one Sr(6)O6 pentagonal pyramid, and  an edgeedge with one Pr(1)O5 tetrahedra. In the fourth Pr site, Pr(4) is bonded in a 6-coordinate geometry to one O(15), one O(18), one O(3), one O(5), one O(8), and one O(9) atom. In the fifth Pr site, Pr(5) is bonded in a 4-coordinate geometry to one O(1), one O(10), one O(12), one O(13), and one O(7) atom. In the sixth Pr site, Pr(6) is bonded to one O(10), one O(11), one O(16), one O(2), one O(6), and one O(7) atom to form distorted PrO6 pentagonal pyramids that share corners with two equivalent Pr(3)O6 pentagonal pyramids,  a cornercorner with one Pr(1)O5 tetrahedra,  an edgeedge with one Sr(1)O6 pentagonal pyramid,  an edgeedge with one Sr(6)O6 pentagonal pyramid, and  an edgeedge with one Pr(2)O6 pentagonal pyramid. In the seventh Pr site, Pr(7) is bonded in a 6-coordinate geometry to one O(12), one O(13), one O(15), one O(18), one O(5), and one O(9) atom. In the eighth Pr site, Pr(8) is bonded in a 6-coordinate geometry to one O(1), one O(12), one O(13), one O(2), one O(3), and one O(4) atom. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded to one Pr(1), one Pr(3), one Pr(5), and one Pr(8) atom to form distorted OPr4 tetrahedra that share  a cornercorner with one O(11)Sr2Pr2 tetrahedra,  a cornercorner with one O(15)SrPr3 tetrahedra,  a cornercorner with one O(2)SrPr3 tetrahedra,  a cornercorner with one O(14)Sr3Pr trigonal pyramid,  a cornercorner with one O(3)SrPr3 trigonal pyramid,  a cornercorner with one O(7)SrPr3 trigonal pyramid, and  a faceface with one O(12)Sr2Pr4 octahedra. In the second O site, O(2) is bonded to one Sr(2), one Pr(2), one Pr(6), and one Pr(8) atom to form OSrPr3 tetrahedra that share  a cornercorner with one O(1)Pr4 tetrahedra,  a cornercorner with one O(11)Sr2Pr2 tetrahedra,  a cornercorner with one O(17)Sr3Pr trigonal pyramid,  a cornercorner with one O(6)Sr3Pr trigonal pyramid,  a cornercorner with one O(3)SrPr3 trigonal pyramid,  an edgeedge with one O(12)Sr2Pr4 octahedra,  an edgeedge with one O(9)Sr2Pr3 trigonal bipyramid,  an edgeedge with one O(3)SrPr3 trigonal pyramid, and  an edgeedge with one O(7)SrPr3 trigonal pyramid. In the third O site, O(3) is bonded to one Sr(2), one Pr(2), one Pr(4), and one Pr(8) atom to form distorted OSrPr3 trigonal pyramids that share corners with two equivalent O(12)Sr2Pr4 octahedra,  a cornercorner with one O(1)Pr4 tetrahedra,  a cornercorner with one O(15)SrPr3 tetrahedra,  a cornercorner with one O(2)SrPr3 tetrahedra,  a cornercorner with one O(9)Sr2Pr3 trigonal bipyramid,  a cornercorner with one O(18)Sr3Pr2 trigonal bipyramid,  a cornercorner with one O(17)Sr3Pr trigonal pyramid,  a cornercorner with one O(7)SrPr3 trigonal pyramid,  an edgeedge with one O(2)SrPr3 tetrahedra, and  an edgeedge with one O(9)Sr2Pr3 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 60-73°. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Sr(2), one Sr(3), one Sr(4), one Pr(1), one Pr(3), and one Pr(8) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Sr(1), one Sr(6), one Pr(3), one Pr(4), and one Pr(7) atom. In the sixth O site, O(6) is bonded to one Sr(1), one Sr(3), one Sr(6), and one Pr(6) atom to form distorted OSr3Pr trigonal pyramids that share  a cornercorner with one O(11)Sr2Pr2 tetrahedra,  a cornercorner with one O(2)SrPr3 tetrahedra,  a cornercorner with one O(9)Sr2Pr3 trigonal bipyramid,  a cornercorner with one O(18)Sr3Pr2 trigonal bipyramid,  a cornercorner with one O(7)SrPr3 trigonal pyramid,  an edgeedge with one O(11)Sr2Pr2 tetrahedra,  an edgeedge with one O(14)Sr3Pr trigonal pyramid, and  an edgeedge with one O(17)Sr3Pr trigonal pyramid. In the seventh O site, O(7) is bonded to one Sr(4), one Pr(2), one Pr(5), and one Pr(6) atom to form distorted OSrPr3 trigonal pyramids that share  a cornercorner with one O(1)Pr4 tetrahedra,  a cornercorner with one O(11)Sr2Pr2 tetrahedra,  a cornercorner with one O(9)Sr2Pr3 trigonal bipyramid,  a cornercorner with one O(18)Sr3Pr2 trigonal bipyramid,  a cornercorner with one O(17)Sr3Pr trigonal pyramid,  a cornercorner with one O(6)Sr3Pr trigonal pyramid,  a cornercorner with one O(3)SrPr3 trigonal pyramid,  an edgeedge with one O(12)Sr2Pr4 octahedra, and  an edgeedge with one O(2)SrPr3 tetrahedra. In the eighth O site, O(8) is bonded in a distorted see-saw-like geometry to one Sr(1), one Sr(3), one Pr(2), and one Pr(4) atom. In the ninth O site, O(9) is bonded to one Sr(1), one Sr(2), one Pr(2), one Pr(4), and one Pr(7) atom to form distorted OSr2Pr3 trigonal bipyramids that share  a cornercorner with one O(11)Sr2Pr2 tetrahedra, corners with two equivalent O(15)SrPr3 tetrahedra,  a cornercorner with one O(6)Sr3Pr trigonal pyramid,  a cornercorner with one O(3)SrPr3 trigonal pyramid,  a cornercorner with one O(7)SrPr3 trigonal pyramid,  an edgeedge with one O(12)Sr2Pr4 octahedra,  an edgeedge with one O(2)SrPr3 tetrahedra,  an edgeedge with one O(18)Sr3Pr2 trigonal bipyramid,  an edgeedge with one O(17)Sr3Pr trigonal pyramid, and  an edgeedge with one O(3)SrPr3 trigonal pyramid. In the tenth O site, O(10) is bonded in a rectangular see-saw-like geometry to one Sr(2), one Sr(3), one Pr(5), and one Pr(6) atom. In the eleventh O site, O(11) is bonded to one Sr(1), one Sr(3), one Pr(3), and one Pr(6) atom to form distorted OSr2Pr2 tetrahedra that share  a cornercorner with one O(12)Sr2Pr4 octahedra,  a cornercorner with one O(1)Pr4 tetrahedra,  a cornercorner with one O(2)SrPr3 tetrahedra,  a cornercorner with one O(9)Sr2Pr3 trigonal bipyramid,  a cornercorner with one O(14)Sr3Pr trigonal pyramid,  a cornercorner with one O(17)Sr3Pr trigonal pyramid,  a cornercorner with one O(6)Sr3Pr trigonal pyramid,  a cornercorner with one O(7)SrPr3 trigonal pyramid, and  an edgeedge with one O(6)Sr3Pr trigonal pyramid. The corner-sharing octahedral tilt angles are 81°. In the twelfth O site, O(12) is bonded to one Sr(2), one Sr(4), one Pr(3), one Pr(5), one Pr(7), and one Pr(8) atom to form distorted OSr2Pr4 octahedra that share  a cornercorner with one O(11)Sr2Pr2 tetrahedra,  a cornercorner with one O(15)SrPr3 tetrahedra, corners with two equivalent O(3)SrPr3 trigonal pyramids,  an edgeedge with one O(2)SrPr3 tetrahedra,  an edgeedge with one O(9)Sr2Pr3 trigonal bipyramid,  an edgeedge with one O(18)Sr3Pr2 trigonal bipyramid,  an edgeedge with one O(7)SrPr3 trigonal pyramid, and  a faceface with one O(1)Pr4 tetrahedra. In the thirteenth O site, O(13) is bonded in a 5-coordinate geometry to one Sr(4), one Sr(5), one Pr(5), one Pr(7), and one Pr(8) atom. In the fourteenth O site, O(14) is bonded to one Sr(3), one Sr(5), one Sr(6), and one Pr(1) atom to form distorted OSr3Pr trigonal pyramids that share  a cornercorner with one O(1)Pr4 tetrahedra,  a cornercorner with one O(11)Sr2Pr2 tetrahedra, corners with two equivalent O(18)Sr3Pr2 trigonal bipyramids, corners with two equivalent O(17)Sr3Pr trigonal pyramids,  an edgeedge with one O(15)SrPr3 tetrahedra, and  an edgeedge with one O(6)Sr3Pr trigonal pyramid. In the fifteenth O site, O(15) is bonded to one Sr(5), one Pr(1), one Pr(4), and one Pr(7) atom to form OSrPr3 tetrahedra that share  a cornercorner with one O(12)Sr2Pr4 octahedra,  a cornercorner with one O(1)Pr4 tetrahedra,  a cornercorner with one O(18)Sr3Pr2 trigonal bipyramid, corners with two equivalent O(9)Sr2Pr3 trigonal bipyramids,  a cornercorner with one O(17)Sr3Pr trigonal pyramid,  a cornercorner with one O(3)SrPr3 trigonal pyramid,  an edgeedge with one O(18)Sr3Pr2 trigonal bipyramid, and  an edgeedge with one O(14)Sr3Pr trigonal pyramid. The corner-sharing octahedral tilt angles are 46°. In the sixteenth O site, O(16) is bonded in a 5-coordinate geometry to one Sr(4), one Sr(6), one Pr(1), one Pr(3), and one Pr(6) atom. In the seventeenth O site, O(17) is bonded to one Sr(1), one Sr(5), one Sr(6), and one Pr(2) atom to form distorted OSr3Pr trigonal pyramids that share  a cornercorner with one O(11)Sr2Pr2 tetrahedra,  a cornercorner with one O(15)SrPr3 tetrahedra,  a cornercorner with one O(2)SrPr3 tetrahedra,  a cornercorner with one O(3)SrPr3 trigonal pyramid,  a cornercorner with one O(7)SrPr3 trigonal pyramid, corners with two equivalent O(14)Sr3Pr trigonal pyramids,  an edgeedge with one O(9)Sr2Pr3 trigonal bipyramid,  an edgeedge with one O(18)Sr3Pr2 trigonal bipyramid, and  an edgeedge with one O(6)Sr3Pr trigonal pyramid. In the eighteenth O site, O(18) is bonded to one Sr(4), one Sr(5), one Sr(6), one Pr(4), and one Pr(7) atom to form distorted OSr3Pr2 trigonal bipyramids that share  a cornercorner with one O(15)SrPr3 tetrahedra,  a cornercorner with one O(6)Sr3Pr trigonal pyramid,  a cornercorner with one O(3)SrPr3 trigonal pyramid,  a cornercorner with one O(7)SrPr3 trigonal pyramid, corners with two equivalent O(14)Sr3Pr trigonal pyramids,  an edgeedge with one O(12)Sr2Pr4 octahedra,  an edgeedge with one O(15)SrPr3 tetrahedra,  an edgeedge with one O(9)Sr2Pr3 trigonal bipyramid, and  an edgeedge with one O(17)Sr3Pr trigonal pyramid. is represented by the CIF file [CIF]
data_Sr3Pr4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.038
_cell_length_b   9.228
_cell_length_c   9.815
_cell_angle_alpha   91.886
_cell_angle_beta   97.105
_cell_angle_gamma   107.519
_symmetry_Int_Tables_number   1
_cell_volume   601.554
_cell_formula_units_Z   2
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  0.090  0.737  0.927  1.0
  Sr  Sr1  1  0.781  0.776  0.426  1.0
  Sr  Sr2  1  0.527  0.624  0.060  1.0
  Sr  Sr3  1  0.838  0.199  0.448  1.0
  Sr  Sr4  1  0.650  0.345  0.732  1.0
  Sr  Sr5  1  0.086  0.322  0.924  1.0
  Pr  Pr6  1  0.515  0.169  0.039  1.0
  Pr  Pr7  1  0.194  0.638  0.619  1.0
  Pr  Pr8  1  0.938  0.003  0.155  1.0
  Pr  Pr9  1  0.688  0.927  0.766  1.0
  Pr  Pr10  1  0.352  0.328  0.356  1.0
  Pr  Pr11  1  0.964  0.528  0.238  1.0
  Pr  Pr12  1  0.173  0.057  0.670  1.0
  Pr  Pr13  1  0.355  0.936  0.373  1.0
  O  O14  1  0.296  0.120  0.200  1.0
  O  O15  1  0.102  0.724  0.406  1.0
  O  O16  1  0.511  0.825  0.552  1.0
  O  O17  1  0.621  0.933  0.253  1.0
  O  O18  1  0.010  0.013  0.927  1.0
  O  O19  1  0.184  0.548  0.087  1.0
  O  O20  1  0.125  0.426  0.446  1.0
  O  O21  1  0.430  0.745  0.849  1.0
  O  O22  1  0.995  0.813  0.668  1.0
  O  O23  1  0.630  0.503  0.303  1.0
  O  O24  1  0.896  0.743  0.123  1.0
  O  O25  1  0.059  0.042  0.420  1.0
  O  O26  1  0.491  0.197  0.511  1.0
  O  O27  1  0.464  0.371  0.935  1.0
  O  O28  1  0.503  0.090  0.812  1.0
  O  O29  1  0.851  0.246  0.130  1.0
  O  O30  1  0.982  0.504  0.771  1.0
  O  O31  1  0.921  0.162  0.684  1.0
[/CIF]
.
The compound described by Sr3Pr4O9 crystallizes in the triclinic P1 space group. There are six inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one O(11), one O(17), one O(5), one O(6), one O(8), and one O(9) atom to form distorted SrO6 pentagonal pyramids that share  a cornercorner with one Sr(6)O6 pentagonal pyramid,  an edgeedge with one Sr(6)O6 pentagonal pyramid,  an edgeedge with one Pr(3)O6 pentagonal pyramid,  an edgeedge with one Pr(6)O6 pentagonal pyramid, and  a faceface with one Pr(2)O6 pentagonal pyramid. In the second Sr site, Sr(2) is bonded in a 6-coordinate geometry to one O(10), one O(12), one O(2), one O(3), one O(4), and one O(9) atom. In the third Sr site, Sr(3) is bonded in a 6-coordinate geometry to one O(10), one O(11), one O(14), one O(4), one O(6), and one O(8) atom. In the fourth Sr site, Sr(4) is bonded in a 6-coordinate geometry to one O(12), one O(13), one O(16), one O(18), one O(4), and one O(7) atom. In the fifth Sr site, Sr(5) is bonded in a 5-coordinate geometry to one O(13), one O(14), one O(15), one O(17), and one O(18) atom. In the sixth Sr site, Sr(6) is bonded to one O(14), one O(16), one O(17), one O(18), one O(5), and one O(6) atom to form distorted SrO6 pentagonal pyramids that share  a cornercorner with one Sr(1)O6 pentagonal pyramid,  a cornercorner with one Pr(2)O6 pentagonal pyramid, corners with two equivalent Pr(1)O5 tetrahedra,  an edgeedge with one Sr(1)O6 pentagonal pyramid,  an edgeedge with one Pr(3)O6 pentagonal pyramid, and  an edgeedge with one Pr(6)O6 pentagonal pyramid. There are eight inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to one O(1), one O(14), one O(15), one O(16), and one O(4) atom to form distorted PrO5 tetrahedra that share  a cornercorner with one Pr(3)O6 pentagonal pyramid,  a cornercorner with one Pr(6)O6 pentagonal pyramid, corners with two equivalent Sr(6)O6 pentagonal pyramids, and  an edgeedge with one Pr(3)O6 pentagonal pyramid. In the second Pr site, Pr(2) is bonded to one O(17), one O(2), one O(3), one O(7), one O(8), and one O(9) atom to form distorted PrO6 pentagonal pyramids that share  a cornercorner with one Sr(6)O6 pentagonal pyramid,  an edgeedge with one Pr(6)O6 pentagonal pyramid, and  a faceface with one Sr(1)O6 pentagonal pyramid. In the third Pr site, Pr(3) is bonded to one O(1), one O(11), one O(12), one O(16), one O(4), and one O(5) atom to form distorted PrO6 pentagonal pyramids that share corners with two equivalent Pr(6)O6 pentagonal pyramids,  a cornercorner with one Pr(1)O5 tetrahedra,  an edgeedge with one Sr(1)O6 pentagonal pyramid,  an edgeedge with one Sr(6)O6 pentagonal pyramid, and  an edgeedge with one Pr(1)O5 tetrahedra. In the fourth Pr site, Pr(4) is bonded in a 6-coordinate geometry to one O(15), one O(18), one O(3), one O(5), one O(8), and one O(9) atom. In the fifth Pr site, Pr(5) is bonded in a 4-coordinate geometry to one O(1), one O(10), one O(12), one O(13), and one O(7) atom. In the sixth Pr site, Pr(6) is bonded to one O(10), one O(11), one O(16), one O(2), one O(6), and one O(7) atom to form distorted PrO6 pentagonal pyramids that share corners with two equivalent Pr(3)O6 pentagonal pyramids,  a cornercorner with one Pr(1)O5 tetrahedra,  an edgeedge with one Sr(1)O6 pentagonal pyramid,  an edgeedge with one Sr(6)O6 pentagonal pyramid, and  an edgeedge with one Pr(2)O6 pentagonal pyramid. In the seventh Pr site, Pr(7) is bonded in a 6-coordinate geometry to one O(12), one O(13), one O(15), one O(18), one O(5), and one O(9) atom. In the eighth Pr site, Pr(8) is bonded in a 6-coordinate geometry to one O(1), one O(12), one O(13), one O(2), one O(3), and one O(4) atom. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded to one Pr(1), one Pr(3), one Pr(5), and one Pr(8) atom to form distorted OPr4 tetrahedra that share  a cornercorner with one O(11)Sr2Pr2 tetrahedra,  a cornercorner with one O(15)SrPr3 tetrahedra,  a cornercorner with one O(2)SrPr3 tetrahedra,  a cornercorner with one O(14)Sr3Pr trigonal pyramid,  a cornercorner with one O(3)SrPr3 trigonal pyramid,  a cornercorner with one O(7)SrPr3 trigonal pyramid, and  a faceface with one O(12)Sr2Pr4 octahedra. In the second O site, O(2) is bonded to one Sr(2), one Pr(2), one Pr(6), and one Pr(8) atom to form OSrPr3 tetrahedra that share  a cornercorner with one O(1)Pr4 tetrahedra,  a cornercorner with one O(11)Sr2Pr2 tetrahedra,  a cornercorner with one O(17)Sr3Pr trigonal pyramid,  a cornercorner with one O(6)Sr3Pr trigonal pyramid,  a cornercorner with one O(3)SrPr3 trigonal pyramid,  an edgeedge with one O(12)Sr2Pr4 octahedra,  an edgeedge with one O(9)Sr2Pr3 trigonal bipyramid,  an edgeedge with one O(3)SrPr3 trigonal pyramid, and  an edgeedge with one O(7)SrPr3 trigonal pyramid. In the third O site, O(3) is bonded to one Sr(2), one Pr(2), one Pr(4), and one Pr(8) atom to form distorted OSrPr3 trigonal pyramids that share corners with two equivalent O(12)Sr2Pr4 octahedra,  a cornercorner with one O(1)Pr4 tetrahedra,  a cornercorner with one O(15)SrPr3 tetrahedra,  a cornercorner with one O(2)SrPr3 tetrahedra,  a cornercorner with one O(9)Sr2Pr3 trigonal bipyramid,  a cornercorner with one O(18)Sr3Pr2 trigonal bipyramid,  a cornercorner with one O(17)Sr3Pr trigonal pyramid,  a cornercorner with one O(7)SrPr3 trigonal pyramid,  an edgeedge with one O(2)SrPr3 tetrahedra, and  an edgeedge with one O(9)Sr2Pr3 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 60-73°. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Sr(2), one Sr(3), one Sr(4), one Pr(1), one Pr(3), and one Pr(8) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Sr(1), one Sr(6), one Pr(3), one Pr(4), and one Pr(7) atom. In the sixth O site, O(6) is bonded to one Sr(1), one Sr(3), one Sr(6), and one Pr(6) atom to form distorted OSr3Pr trigonal pyramids that share  a cornercorner with one O(11)Sr2Pr2 tetrahedra,  a cornercorner with one O(2)SrPr3 tetrahedra,  a cornercorner with one O(9)Sr2Pr3 trigonal bipyramid,  a cornercorner with one O(18)Sr3Pr2 trigonal bipyramid,  a cornercorner with one O(7)SrPr3 trigonal pyramid,  an edgeedge with one O(11)Sr2Pr2 tetrahedra,  an edgeedge with one O(14)Sr3Pr trigonal pyramid, and  an edgeedge with one O(17)Sr3Pr trigonal pyramid. In the seventh O site, O(7) is bonded to one Sr(4), one Pr(2), one Pr(5), and one Pr(6) atom to form distorted OSrPr3 trigonal pyramids that share  a cornercorner with one O(1)Pr4 tetrahedra,  a cornercorner with one O(11)Sr2Pr2 tetrahedra,  a cornercorner with one O(9)Sr2Pr3 trigonal bipyramid,  a cornercorner with one O(18)Sr3Pr2 trigonal bipyramid,  a cornercorner with one O(17)Sr3Pr trigonal pyramid,  a cornercorner with one O(6)Sr3Pr trigonal pyramid,  a cornercorner with one O(3)SrPr3 trigonal pyramid,  an edgeedge with one O(12)Sr2Pr4 octahedra, and  an edgeedge with one O(2)SrPr3 tetrahedra. In the eighth O site, O(8) is bonded in a distorted see-saw-like geometry to one Sr(1), one Sr(3), one Pr(2), and one Pr(4) atom. In the ninth O site, O(9) is bonded to one Sr(1), one Sr(2), one Pr(2), one Pr(4), and one Pr(7) atom to form distorted OSr2Pr3 trigonal bipyramids that share  a cornercorner with one O(11)Sr2Pr2 tetrahedra, corners with two equivalent O(15)SrPr3 tetrahedra,  a cornercorner with one O(6)Sr3Pr trigonal pyramid,  a cornercorner with one O(3)SrPr3 trigonal pyramid,  a cornercorner with one O(7)SrPr3 trigonal pyramid,  an edgeedge with one O(12)Sr2Pr4 octahedra,  an edgeedge with one O(2)SrPr3 tetrahedra,  an edgeedge with one O(18)Sr3Pr2 trigonal bipyramid,  an edgeedge with one O(17)Sr3Pr trigonal pyramid, and  an edgeedge with one O(3)SrPr3 trigonal pyramid. In the tenth O site, O(10) is bonded in a rectangular see-saw-like geometry to one Sr(2), one Sr(3), one Pr(5), and one Pr(6) atom. In the eleventh O site, O(11) is bonded to one Sr(1), one Sr(3), one Pr(3), and one Pr(6) atom to form distorted OSr2Pr2 tetrahedra that share  a cornercorner with one O(12)Sr2Pr4 octahedra,  a cornercorner with one O(1)Pr4 tetrahedra,  a cornercorner with one O(2)SrPr3 tetrahedra,  a cornercorner with one O(9)Sr2Pr3 trigonal bipyramid,  a cornercorner with one O(14)Sr3Pr trigonal pyramid,  a cornercorner with one O(17)Sr3Pr trigonal pyramid,  a cornercorner with one O(6)Sr3Pr trigonal pyramid,  a cornercorner with one O(7)SrPr3 trigonal pyramid, and  an edgeedge with one O(6)Sr3Pr trigonal pyramid. The corner-sharing octahedral tilt angles are 81°. In the twelfth O site, O(12) is bonded to one Sr(2), one Sr(4), one Pr(3), one Pr(5), one Pr(7), and one Pr(8) atom to form distorted OSr2Pr4 octahedra that share  a cornercorner with one O(11)Sr2Pr2 tetrahedra,  a cornercorner with one O(15)SrPr3 tetrahedra, corners with two equivalent O(3)SrPr3 trigonal pyramids,  an edgeedge with one O(2)SrPr3 tetrahedra,  an edgeedge with one O(9)Sr2Pr3 trigonal bipyramid,  an edgeedge with one O(18)Sr3Pr2 trigonal bipyramid,  an edgeedge with one O(7)SrPr3 trigonal pyramid, and  a faceface with one O(1)Pr4 tetrahedra. In the thirteenth O site, O(13) is bonded in a 5-coordinate geometry to one Sr(4), one Sr(5), one Pr(5), one Pr(7), and one Pr(8) atom. In the fourteenth O site, O(14) is bonded to one Sr(3), one Sr(5), one Sr(6), and one Pr(1) atom to form distorted OSr3Pr trigonal pyramids that share  a cornercorner with one O(1)Pr4 tetrahedra,  a cornercorner with one O(11)Sr2Pr2 tetrahedra, corners with two equivalent O(18)Sr3Pr2 trigonal bipyramids, corners with two equivalent O(17)Sr3Pr trigonal pyramids,  an edgeedge with one O(15)SrPr3 tetrahedra, and  an edgeedge with one O(6)Sr3Pr trigonal pyramid. In the fifteenth O site, O(15) is bonded to one Sr(5), one Pr(1), one Pr(4), and one Pr(7) atom to form OSrPr3 tetrahedra that share  a cornercorner with one O(12)Sr2Pr4 octahedra,  a cornercorner with one O(1)Pr4 tetrahedra,  a cornercorner with one O(18)Sr3Pr2 trigonal bipyramid, corners with two equivalent O(9)Sr2Pr3 trigonal bipyramids,  a cornercorner with one O(17)Sr3Pr trigonal pyramid,  a cornercorner with one O(3)SrPr3 trigonal pyramid,  an edgeedge with one O(18)Sr3Pr2 trigonal bipyramid, and  an edgeedge with one O(14)Sr3Pr trigonal pyramid. The corner-sharing octahedral tilt angles are 46°. In the sixteenth O site, O(16) is bonded in a 5-coordinate geometry to one Sr(4), one Sr(6), one Pr(1), one Pr(3), and one Pr(6) atom. In the seventeenth O site, O(17) is bonded to one Sr(1), one Sr(5), one Sr(6), and one Pr(2) atom to form distorted OSr3Pr trigonal pyramids that share  a cornercorner with one O(11)Sr2Pr2 tetrahedra,  a cornercorner with one O(15)SrPr3 tetrahedra,  a cornercorner with one O(2)SrPr3 tetrahedra,  a cornercorner with one O(3)SrPr3 trigonal pyramid,  a cornercorner with one O(7)SrPr3 trigonal pyramid, corners with two equivalent O(14)Sr3Pr trigonal pyramids,  an edgeedge with one O(9)Sr2Pr3 trigonal bipyramid,  an edgeedge with one O(18)Sr3Pr2 trigonal bipyramid, and  an edgeedge with one O(6)Sr3Pr trigonal pyramid. In the eighteenth O site, O(18) is bonded to one Sr(4), one Sr(5), one Sr(6), one Pr(4), and one Pr(7) atom to form distorted OSr3Pr2 trigonal bipyramids that share  a cornercorner with one O(15)SrPr3 tetrahedra,  a cornercorner with one O(6)Sr3Pr trigonal pyramid,  a cornercorner with one O(3)SrPr3 trigonal pyramid,  a cornercorner with one O(7)SrPr3 trigonal pyramid, corners with two equivalent O(14)Sr3Pr trigonal pyramids,  an edgeedge with one O(12)Sr2Pr4 octahedra,  an edgeedge with one O(15)SrPr3 tetrahedra,  an edgeedge with one O(9)Sr2Pr3 trigonal bipyramid, and  an edgeedge with one O(17)Sr3Pr trigonal pyramid. is represented by the CIF file [CIF]
data_Sr3Pr4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.038
_cell_length_b   9.228
_cell_length_c   9.815
_cell_angle_alpha   91.886
_cell_angle_beta   97.105
_cell_angle_gamma   107.519
_symmetry_Int_Tables_number   1
_cell_volume   601.554
_cell_formula_units_Z   2
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  0.090  0.737  0.927  1.0
  Sr  Sr1  1  0.781  0.776  0.426  1.0
  Sr  Sr2  1  0.527  0.624  0.060  1.0
  Sr  Sr3  1  0.838  0.199  0.448  1.0
  Sr  Sr4  1  0.650  0.345  0.732  1.0
  Sr  Sr5  1  0.086  0.322  0.924  1.0
  Pr  Pr6  1  0.515  0.169  0.039  1.0
  Pr  Pr7  1  0.194  0.638  0.619  1.0
  Pr  Pr8  1  0.938  0.003  0.155  1.0
  Pr  Pr9  1  0.688  0.927  0.766  1.0
  Pr  Pr10  1  0.352  0.328  0.356  1.0
  Pr  Pr11  1  0.964  0.528  0.238  1.0
  Pr  Pr12  1  0.173  0.057  0.670  1.0
  Pr  Pr13  1  0.355  0.936  0.373  1.0
  O  O14  1  0.296  0.120  0.200  1.0
  O  O15  1  0.102  0.724  0.406  1.0
  O  O16  1  0.511  0.825  0.552  1.0
  O  O17  1  0.621  0.933  0.253  1.0
  O  O18  1  0.010  0.013  0.927  1.0
  O  O19  1  0.184  0.548  0.087  1.0
  O  O20  1  0.125  0.426  0.446  1.0
  O  O21  1  0.430  0.745  0.849  1.0
  O  O22  1  0.995  0.813  0.668  1.0
  O  O23  1  0.630  0.503  0.303  1.0
  O  O24  1  0.896  0.743  0.123  1.0
  O  O25  1  0.059  0.042  0.420  1.0
  O  O26  1  0.491  0.197  0.511  1.0
  O  O27  1  0.464  0.371  0.935  1.0
  O  O28  1  0.503  0.090  0.812  1.0
  O  O29  1  0.851  0.246  0.130  1.0
  O  O30  1  0.982  0.504  0.771  1.0
  O  O31  1  0.921  0.162  0.684  1.0
[/CIF]
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