The crystal structure described by Sr3LaI9 crystallizes in the monoclinic Pc space group. There are six inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one I(1), one I(10), one I(13), one I(14), one I(4), one I(5), and one I(9) atom to form distorted SrI7 pentagonal bipyramids that share corners with two equivalent Sr(6)I7 pentagonal bipyramids, corners with two equivalent La(2)I7 pentagonal bipyramids,  an edgeedge with one Sr(3)I7 pentagonal bipyramid, and edges with two equivalent Sr(6)I7 pentagonal bipyramids. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to one I(11), one I(12), one I(15), one I(2), one I(3), one I(6), one I(7), and one I(8) atom. In the third Sr site, Sr(3) is bonded to one I(12), one I(13), one I(17), one I(18), one I(3), one I(8), and one I(9) atom to form distorted SrI7 pentagonal bipyramids that share corners with two equivalent Sr(6)I7 pentagonal bipyramids, corners with two equivalent La(2)I7 pentagonal bipyramids,  an edgeedge with one Sr(1)I7 pentagonal bipyramid, and edges with two equivalent La(2)I7 pentagonal bipyramids. In the fourth Sr site, Sr(4) is bonded in a 8-coordinate geometry to one I(1), one I(10), one I(11), one I(14), one I(15), one I(16), one I(2), and one I(7) atom. In the fifth Sr site, Sr(5) is bonded in a 8-coordinate geometry to one I(11), one I(12), one I(15), one I(16), one I(17), one I(2), one I(3), and one I(6) atom. In the sixth Sr site, Sr(6) is bonded to one I(1), one I(10), one I(13), one I(14), one I(18), one I(4), and one I(5) atom to form distorted SrI7 pentagonal bipyramids that share corners with two equivalent Sr(1)I7 pentagonal bipyramids, corners with two equivalent Sr(3)I7 pentagonal bipyramids,  an edgeedge with one La(2)I7 pentagonal bipyramid, and edges with two equivalent Sr(1)I7 pentagonal bipyramids. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 8-coordinate geometry to one I(1), one I(10), one I(11), one I(16), one I(2), one I(5), one I(6), and one I(7) atom. In the second La site, La(2) is bonded to one I(12), one I(17), one I(18), one I(3), one I(4), one I(8), and one I(9) atom to form distorted LaI7 pentagonal bipyramids that share corners with two equivalent Sr(1)I7 pentagonal bipyramids, corners with two equivalent Sr(3)I7 pentagonal bipyramids,  an edgeedge with one Sr(6)I7 pentagonal bipyramid, and edges with two equivalent Sr(3)I7 pentagonal bipyramids. There are eighteen inequivalent I sites. In the first I site, I(1) is bonded to one Sr(1), one Sr(4), one Sr(6), and one La(1) atom to form a mixture of edge and corner-sharing ISr3La tetrahedra. In the second I site, I(2) is bonded to one Sr(2), one Sr(4), one Sr(5), and one La(1) atom to form a mixture of distorted edge and corner-sharing ISr3La tetrahedra. In the third I site, I(3) is bonded to one Sr(2), one Sr(3), one Sr(5), and one La(2) atom to form a mixture of edge and corner-sharing ISr3La tetrahedra. In the fourth I site, I(4) is bonded in a trigonal non-coplanar geometry to one Sr(1), one Sr(6), and one La(2) atom. In the fifth I site, I(5) is bonded in a trigonal planar geometry to one Sr(1), one Sr(6), and one La(1) atom. In the sixth I site, I(6) is bonded in a distorted trigonal non-coplanar geometry to one Sr(2), one Sr(5), and one La(1) atom. In the seventh I site, I(7) is bonded in a distorted trigonal non-coplanar geometry to one Sr(2), one Sr(4), and one La(1) atom. In the eighth I site, I(8) is bonded in a distorted trigonal planar geometry to one Sr(2), one Sr(3), and one La(2) atom. In the ninth I site, I(9) is bonded in a trigonal non-coplanar geometry to one Sr(1), one Sr(3), and one La(2) atom. In the tenth I site, I(10) is bonded to one Sr(1), one Sr(4), one Sr(6), and one La(1) atom to form a mixture of distorted edge and corner-sharing ISr3La tetrahedra. In the eleventh I site, I(11) is bonded to one Sr(2), one Sr(4), one Sr(5), and one La(1) atom to form a mixture of edge and corner-sharing ISr3La tetrahedra. In the twelfth I site, I(12) is bonded to one Sr(2), one Sr(3), one Sr(5), and one La(2) atom to form a mixture of edge and corner-sharing ISr3La tetrahedra. In the thirteenth I site, I(13) is bonded in a trigonal non-coplanar geometry to one Sr(1), one Sr(3), and one Sr(6) atom. In the fourteenth I site, I(14) is bonded in a trigonal planar geometry to one Sr(1), one Sr(4), and one Sr(6) atom. In the fifteenth I site, I(15) is bonded in a distorted trigonal non-coplanar geometry to one Sr(2), one Sr(4), and one Sr(5) atom. In the sixteenth I site, I(16) is bonded in a distorted trigonal non-coplanar geometry to one Sr(4), one Sr(5), and one La(1) atom. In the seventeenth I site, I(17) is bonded in a trigonal planar geometry to one Sr(3), one Sr(5), and one La(2) atom. In the eighteenth I site, I(18) is bonded in a trigonal non-coplanar geometry to one Sr(3), one Sr(6), and one La(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sr3LaI9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.802
_cell_length_b   8.405
_cell_length_c   33.107
_cell_angle_alpha   88.208
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   2170.037
_cell_formula_units_Z   4
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  0.967  0.668  0.933  1.0
  Sr  Sr1  1  0.002  0.700  0.692  1.0
  Sr  Sr2  1  0.033  0.668  0.433  1.0
  Sr  Sr3  1  0.998  0.700  0.192  1.0
  Sr  Sr4  1  0.985  0.321  0.569  1.0
  Sr  Sr5  1  0.982  0.286  0.810  1.0
  Sr  Sr6  1  0.015  0.321  0.069  1.0
  Sr  Sr7  1  0.018  0.286  0.310  1.0
  Sr  Sr8  1  0.523  0.210  0.692  1.0
  Sr  Sr9  1  0.517  0.172  0.932  1.0
  Sr  Sr10  1  0.477  0.210  0.192  1.0
  Sr  Sr11  1  0.483  0.172  0.432  1.0
  La  La12  1  0.521  0.799  0.807  1.0
  La  La13  1  0.547  0.823  0.568  1.0
  La  La14  1  0.479  0.799  0.307  1.0
  La  La15  1  0.453  0.823  0.068  1.0
  I  I16  1  0.801  0.985  0.870  1.0
  I  I17  1  0.823  0.991  0.751  1.0
  I  I18  1  0.820  0.999  0.629  1.0
  I  I19  1  0.199  0.985  0.370  1.0
  I  I20  1  0.177  0.991  0.251  1.0
  I  I21  1  0.710  0.889  0.991  1.0
  I  I22  1  0.180  0.999  0.129  1.0
  I  I23  1  0.325  0.848  0.895  1.0
  I  I24  1  0.290  0.889  0.491  1.0
  I  I25  1  0.391  0.843  0.706  1.0
  I  I26  1  0.675  0.848  0.395  1.0
  I  I27  1  0.609  0.843  0.206  1.0
  I  I28  1  0.153  0.643  0.796  1.0
  I  I29  1  0.200  0.648  0.599  1.0
  I  I30  1  0.847  0.643  0.296  1.0
  I  I31  1  0.800  0.648  0.099  1.0
  I  I32  1  0.754  0.587  0.510  1.0
  I  I33  1  0.682  0.502  0.868  1.0
  I  I34  1  0.694  0.506  0.751  1.0
  I  I35  1  0.701  0.517  0.629  1.0
  I  I36  1  0.246  0.587  0.010  1.0
  I  I37  1  0.318  0.502  0.368  1.0
  I  I38  1  0.306  0.506  0.251  1.0
  I  I39  1  0.299  0.517  0.129  1.0
  I  I40  1  0.762  0.391  0.989  1.0
  I  I41  1  0.238  0.391  0.489  1.0
  I  I42  1  0.160  0.344  0.900  1.0
  I  I43  1  0.123  0.329  0.699  1.0
  I  I44  1  0.840  0.344  0.400  1.0
  I  I45  1  0.877  0.329  0.199  1.0
  I  I46  1  0.384  0.154  0.797  1.0
  I  I47  1  0.349  0.134  0.599  1.0
  I  I48  1  0.616  0.154  0.297  1.0
  I  I49  1  0.651  0.134  0.099  1.0
  I  I50  1  0.758  0.077  0.510  1.0
  I  I51  1  0.242  0.077  0.010  1.0
[/CIF]
.
The crystal structure described by Sr3LaI9 crystallizes in the monoclinic Pc space group. There are six inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one I(1), one I(10), one I(13), one I(14), one I(4), one I(5), and one I(9) atom to form distorted SrI7 pentagonal bipyramids that share corners with two equivalent Sr(6)I7 pentagonal bipyramids, corners with two equivalent La(2)I7 pentagonal bipyramids,  an edgeedge with one Sr(3)I7 pentagonal bipyramid, and edges with two equivalent Sr(6)I7 pentagonal bipyramids. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to one I(11), one I(12), one I(15), one I(2), one I(3), one I(6), one I(7), and one I(8) atom. In the third Sr site, Sr(3) is bonded to one I(12), one I(13), one I(17), one I(18), one I(3), one I(8), and one I(9) atom to form distorted SrI7 pentagonal bipyramids that share corners with two equivalent Sr(6)I7 pentagonal bipyramids, corners with two equivalent La(2)I7 pentagonal bipyramids,  an edgeedge with one Sr(1)I7 pentagonal bipyramid, and edges with two equivalent La(2)I7 pentagonal bipyramids. In the fourth Sr site, Sr(4) is bonded in a 8-coordinate geometry to one I(1), one I(10), one I(11), one I(14), one I(15), one I(16), one I(2), and one I(7) atom. In the fifth Sr site, Sr(5) is bonded in a 8-coordinate geometry to one I(11), one I(12), one I(15), one I(16), one I(17), one I(2), one I(3), and one I(6) atom. In the sixth Sr site, Sr(6) is bonded to one I(1), one I(10), one I(13), one I(14), one I(18), one I(4), and one I(5) atom to form distorted SrI7 pentagonal bipyramids that share corners with two equivalent Sr(1)I7 pentagonal bipyramids, corners with two equivalent Sr(3)I7 pentagonal bipyramids,  an edgeedge with one La(2)I7 pentagonal bipyramid, and edges with two equivalent Sr(1)I7 pentagonal bipyramids. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 8-coordinate geometry to one I(1), one I(10), one I(11), one I(16), one I(2), one I(5), one I(6), and one I(7) atom. In the second La site, La(2) is bonded to one I(12), one I(17), one I(18), one I(3), one I(4), one I(8), and one I(9) atom to form distorted LaI7 pentagonal bipyramids that share corners with two equivalent Sr(1)I7 pentagonal bipyramids, corners with two equivalent Sr(3)I7 pentagonal bipyramids,  an edgeedge with one Sr(6)I7 pentagonal bipyramid, and edges with two equivalent Sr(3)I7 pentagonal bipyramids. There are eighteen inequivalent I sites. In the first I site, I(1) is bonded to one Sr(1), one Sr(4), one Sr(6), and one La(1) atom to form a mixture of edge and corner-sharing ISr3La tetrahedra. In the second I site, I(2) is bonded to one Sr(2), one Sr(4), one Sr(5), and one La(1) atom to form a mixture of distorted edge and corner-sharing ISr3La tetrahedra. In the third I site, I(3) is bonded to one Sr(2), one Sr(3), one Sr(5), and one La(2) atom to form a mixture of edge and corner-sharing ISr3La tetrahedra. In the fourth I site, I(4) is bonded in a trigonal non-coplanar geometry to one Sr(1), one Sr(6), and one La(2) atom. In the fifth I site, I(5) is bonded in a trigonal planar geometry to one Sr(1), one Sr(6), and one La(1) atom. In the sixth I site, I(6) is bonded in a distorted trigonal non-coplanar geometry to one Sr(2), one Sr(5), and one La(1) atom. In the seventh I site, I(7) is bonded in a distorted trigonal non-coplanar geometry to one Sr(2), one Sr(4), and one La(1) atom. In the eighth I site, I(8) is bonded in a distorted trigonal planar geometry to one Sr(2), one Sr(3), and one La(2) atom. In the ninth I site, I(9) is bonded in a trigonal non-coplanar geometry to one Sr(1), one Sr(3), and one La(2) atom. In the tenth I site, I(10) is bonded to one Sr(1), one Sr(4), one Sr(6), and one La(1) atom to form a mixture of distorted edge and corner-sharing ISr3La tetrahedra. In the eleventh I site, I(11) is bonded to one Sr(2), one Sr(4), one Sr(5), and one La(1) atom to form a mixture of edge and corner-sharing ISr3La tetrahedra. In the twelfth I site, I(12) is bonded to one Sr(2), one Sr(3), one Sr(5), and one La(2) atom to form a mixture of edge and corner-sharing ISr3La tetrahedra. In the thirteenth I site, I(13) is bonded in a trigonal non-coplanar geometry to one Sr(1), one Sr(3), and one Sr(6) atom. In the fourteenth I site, I(14) is bonded in a trigonal planar geometry to one Sr(1), one Sr(4), and one Sr(6) atom. In the fifteenth I site, I(15) is bonded in a distorted trigonal non-coplanar geometry to one Sr(2), one Sr(4), and one Sr(5) atom. In the sixteenth I site, I(16) is bonded in a distorted trigonal non-coplanar geometry to one Sr(4), one Sr(5), and one La(1) atom. In the seventeenth I site, I(17) is bonded in a trigonal planar geometry to one Sr(3), one Sr(5), and one La(2) atom. In the eighteenth I site, I(18) is bonded in a trigonal non-coplanar geometry to one Sr(3), one Sr(6), and one La(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sr3LaI9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.802
_cell_length_b   8.405
_cell_length_c   33.107
_cell_angle_alpha   88.208
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   2170.037
_cell_formula_units_Z   4
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  0.967  0.668  0.933  1.0
  Sr  Sr1  1  0.002  0.700  0.692  1.0
  Sr  Sr2  1  0.033  0.668  0.433  1.0
  Sr  Sr3  1  0.998  0.700  0.192  1.0
  Sr  Sr4  1  0.985  0.321  0.569  1.0
  Sr  Sr5  1  0.982  0.286  0.810  1.0
  Sr  Sr6  1  0.015  0.321  0.069  1.0
  Sr  Sr7  1  0.018  0.286  0.310  1.0
  Sr  Sr8  1  0.523  0.210  0.692  1.0
  Sr  Sr9  1  0.517  0.172  0.932  1.0
  Sr  Sr10  1  0.477  0.210  0.192  1.0
  Sr  Sr11  1  0.483  0.172  0.432  1.0
  La  La12  1  0.521  0.799  0.807  1.0
  La  La13  1  0.547  0.823  0.568  1.0
  La  La14  1  0.479  0.799  0.307  1.0
  La  La15  1  0.453  0.823  0.068  1.0
  I  I16  1  0.801  0.985  0.870  1.0
  I  I17  1  0.823  0.991  0.751  1.0
  I  I18  1  0.820  0.999  0.629  1.0
  I  I19  1  0.199  0.985  0.370  1.0
  I  I20  1  0.177  0.991  0.251  1.0
  I  I21  1  0.710  0.889  0.991  1.0
  I  I22  1  0.180  0.999  0.129  1.0
  I  I23  1  0.325  0.848  0.895  1.0
  I  I24  1  0.290  0.889  0.491  1.0
  I  I25  1  0.391  0.843  0.706  1.0
  I  I26  1  0.675  0.848  0.395  1.0
  I  I27  1  0.609  0.843  0.206  1.0
  I  I28  1  0.153  0.643  0.796  1.0
  I  I29  1  0.200  0.648  0.599  1.0
  I  I30  1  0.847  0.643  0.296  1.0
  I  I31  1  0.800  0.648  0.099  1.0
  I  I32  1  0.754  0.587  0.510  1.0
  I  I33  1  0.682  0.502  0.868  1.0
  I  I34  1  0.694  0.506  0.751  1.0
  I  I35  1  0.701  0.517  0.629  1.0
  I  I36  1  0.246  0.587  0.010  1.0
  I  I37  1  0.318  0.502  0.368  1.0
  I  I38  1  0.306  0.506  0.251  1.0
  I  I39  1  0.299  0.517  0.129  1.0
  I  I40  1  0.762  0.391  0.989  1.0
  I  I41  1  0.238  0.391  0.489  1.0
  I  I42  1  0.160  0.344  0.900  1.0
  I  I43  1  0.123  0.329  0.699  1.0
  I  I44  1  0.840  0.344  0.400  1.0
  I  I45  1  0.877  0.329  0.199  1.0
  I  I46  1  0.384  0.154  0.797  1.0
  I  I47  1  0.349  0.134  0.599  1.0
  I  I48  1  0.616  0.154  0.297  1.0
  I  I49  1  0.651  0.134  0.099  1.0
  I  I50  1  0.758  0.077  0.510  1.0
  I  I51  1  0.242  0.077  0.010  1.0
[/CIF]
.