The material described by Rb2KCrF6 crystallizes in the tetragonal I4/m space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded to four equivalent F(4), four equivalent F(5), and four equivalent F(7) atoms to form RbF12 cuboctahedra that share faces with two equivalent Rb(1)F12 cuboctahedra, faces with four equivalent Cr(2)F6 octahedra, and faces with four equivalent K(2)F7 pentagonal bipyramids. In the second Rb site, Rb(2) is bonded in a 11-coordinate geometry to one F(1), one F(2), one F(4), one F(5), two equivalent F(3), two equivalent F(6), and three equivalent F(7) atoms. There are two inequivalent K sites. In the first K site, K(1) is bonded to two equivalent F(2) and four equivalent F(3) atoms to form KF6 octahedra that share corners with two equivalent Cr(1)F6 octahedra and corners with four equivalent Cr(2)F6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the second K site, K(2) is bonded to one F(4), one F(5), one F(6), two equivalent F(1), and two equivalent F(7) atoms to form distorted KF7 pentagonal bipyramids that share corners with five equivalent Cr(2)F6 octahedra, corners with two equivalent K(2)F7 pentagonal bipyramids,  an edgeedge with one Cr(1)F6 octahedra, and faces with two equivalent Rb(1)F12 cuboctahedra. The corner-sharing octahedral tilt angles range from 1-15°. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent F(2) and four equivalent F(1) atoms to form CrF6 octahedra that share corners with two equivalent K(1)F6 octahedra and edges with four equivalent K(2)F7 pentagonal bipyramids. The corner-sharing octahedra are not tilted. In the second Cr site, Cr(2) is bonded to one F(3), one F(4), one F(5), one F(6), and two equivalent F(7) atoms to form CrF6 octahedra that share  a cornercorner with one K(1)F6 octahedra, corners with five equivalent K(2)F7 pentagonal bipyramids, and faces with two equivalent Rb(1)F12 cuboctahedra. The corner-sharing octahedral tilt angles are 1°. There are seven inequivalent F sites. In the first F site, F(1) is bonded in a 5-coordinate geometry to two equivalent Rb(2), two equivalent K(2), and one Cr(1) atom. In the second F site, F(2) is bonded in a distorted linear geometry to four equivalent Rb(2), one K(1), and one Cr(1) atom. In the third F site, F(3) is bonded in a 2-coordinate geometry to four equivalent Rb(2), one K(1), and one Cr(2) atom. In the fourth F site, F(4) is bonded in a distorted single-bond geometry to two equivalent Rb(1), two equivalent Rb(2), one K(2), and one Cr(2) atom. In the fifth F site, F(5) is bonded in a 2-coordinate geometry to two equivalent Rb(1), two equivalent Rb(2), one K(2), and one Cr(2) atom. In the sixth F site, F(7) is bonded in a 6-coordinate geometry to one Rb(1), three equivalent Rb(2), one K(2), and one Cr(2) atom. In the seventh F site, F(6) is bonded in a 6-coordinate geometry to four equivalent Rb(2), one K(2), and one Cr(2) atom. is represented by the CIF card [CIF]
data_KRb2CrF6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.850
_cell_length_b   10.612
_cell_length_c   10.612
_cell_angle_alpha   79.986
_cell_angle_beta   65.355
_cell_angle_gamma   65.355
_symmetry_Int_Tables_number   1
_cell_volume   823.397
_cell_formula_units_Z   5
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
  K  K0  1  0.500  0.000  0.000  1.0
  K  K1  1  0.263  0.825  0.649  1.0
  K  K2  1  0.088  0.649  0.175  1.0
  K  K3  1  0.737  0.175  0.351  1.0
  K  K4  1  0.912  0.351  0.825  1.0
  Rb  Rb5  1  0.750  0.500  0.500  1.0
  Rb  Rb6  1  0.250  0.500  0.500  1.0
  Rb  Rb7  1  0.619  0.894  0.318  1.0
  Rb  Rb8  1  0.514  0.318  0.106  1.0
  Rb  Rb9  1  0.832  0.106  0.682  1.0
  Rb  Rb10  1  0.938  0.682  0.894  1.0
  Rb  Rb11  1  0.381  0.106  0.682  1.0
  Rb  Rb12  1  0.486  0.682  0.894  1.0
  Rb  Rb13  1  0.168  0.894  0.318  1.0
  Rb  Rb14  1  0.062  0.318  0.106  1.0
  Cr  Cr15  1  0.000  0.000  0.000  1.0
  Cr  Cr16  1  0.804  0.791  0.601  1.0
  Cr  Cr17  1  0.595  0.601  0.209  1.0
  Cr  Cr18  1  0.196  0.209  0.399  1.0
  Cr  Cr19  1  0.405  0.399  0.791  1.0
  F  F20  1  0.937  0.937  0.189  1.0
  F  F21  1  0.874  0.189  0.063  1.0
  F  F22  1  0.063  0.063  0.811  1.0
  F  F23  1  0.126  0.811  0.937  1.0
  F  F24  1  0.784  0.000  0.000  1.0
  F  F25  1  0.216  0.000  0.000  1.0
  F  F26  1  0.672  0.880  0.777  1.0
  F  F27  1  0.552  0.777  0.120  1.0
  F  F28  1  0.328  0.120  0.223  1.0
  F  F29  1  0.448  0.223  0.880  1.0
  F  F30  1  0.847  0.613  0.693  1.0
  F  F31  1  0.460  0.693  0.387  1.0
  F  F32  1  0.153  0.387  0.307  1.0
  F  F33  1  0.540  0.307  0.613  1.0
  F  F34  1  0.936  0.701  0.426  1.0
  F  F35  1  0.637  0.426  0.299  1.0
  F  F36  1  0.064  0.299  0.574  1.0
  F  F37  1  0.363  0.574  0.701  1.0
  F  F38  1  0.759  0.969  0.513  1.0
  F  F39  1  0.728  0.513  0.031  1.0
  F  F40  1  0.241  0.031  0.487  1.0
  F  F41  1  0.272  0.487  0.969  1.0
  F  F42  1  0.584  0.795  0.603  1.0
  F  F43  1  0.378  0.603  0.205  1.0
  F  F44  1  0.982  0.205  0.397  1.0
  F  F45  1  0.187  0.397  0.795  1.0
  F  F46  1  0.416  0.205  0.397  1.0
  F  F47  1  0.622  0.397  0.795  1.0
  F  F48  1  0.018  0.795  0.603  1.0
  F  F49  1  0.813  0.603  0.205  1.0
[/CIF]
.
The material described by Rb2KCrF6 crystallizes in the tetragonal I4/m space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded to four equivalent F(4), four equivalent F(5), and four equivalent F(7) atoms to form RbF12 cuboctahedra that share faces with two equivalent Rb(1)F12 cuboctahedra, faces with four equivalent Cr(2)F6 octahedra, and faces with four equivalent K(2)F7 pentagonal bipyramids. In the second Rb site, Rb(2) is bonded in a 11-coordinate geometry to one F(1), one F(2), one F(4), one F(5), two equivalent F(3), two equivalent F(6), and three equivalent F(7) atoms. There are two inequivalent K sites. In the first K site, K(1) is bonded to two equivalent F(2) and four equivalent F(3) atoms to form KF6 octahedra that share corners with two equivalent Cr(1)F6 octahedra and corners with four equivalent Cr(2)F6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the second K site, K(2) is bonded to one F(4), one F(5), one F(6), two equivalent F(1), and two equivalent F(7) atoms to form distorted KF7 pentagonal bipyramids that share corners with five equivalent Cr(2)F6 octahedra, corners with two equivalent K(2)F7 pentagonal bipyramids,  an edgeedge with one Cr(1)F6 octahedra, and faces with two equivalent Rb(1)F12 cuboctahedra. The corner-sharing octahedral tilt angles range from 1-15°. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent F(2) and four equivalent F(1) atoms to form CrF6 octahedra that share corners with two equivalent K(1)F6 octahedra and edges with four equivalent K(2)F7 pentagonal bipyramids. The corner-sharing octahedra are not tilted. In the second Cr site, Cr(2) is bonded to one F(3), one F(4), one F(5), one F(6), and two equivalent F(7) atoms to form CrF6 octahedra that share  a cornercorner with one K(1)F6 octahedra, corners with five equivalent K(2)F7 pentagonal bipyramids, and faces with two equivalent Rb(1)F12 cuboctahedra. The corner-sharing octahedral tilt angles are 1°. There are seven inequivalent F sites. In the first F site, F(1) is bonded in a 5-coordinate geometry to two equivalent Rb(2), two equivalent K(2), and one Cr(1) atom. In the second F site, F(2) is bonded in a distorted linear geometry to four equivalent Rb(2), one K(1), and one Cr(1) atom. In the third F site, F(3) is bonded in a 2-coordinate geometry to four equivalent Rb(2), one K(1), and one Cr(2) atom. In the fourth F site, F(4) is bonded in a distorted single-bond geometry to two equivalent Rb(1), two equivalent Rb(2), one K(2), and one Cr(2) atom. In the fifth F site, F(5) is bonded in a 2-coordinate geometry to two equivalent Rb(1), two equivalent Rb(2), one K(2), and one Cr(2) atom. In the sixth F site, F(7) is bonded in a 6-coordinate geometry to one Rb(1), three equivalent Rb(2), one K(2), and one Cr(2) atom. In the seventh F site, F(6) is bonded in a 6-coordinate geometry to four equivalent Rb(2), one K(2), and one Cr(2) atom. is represented by the CIF card [CIF]
data_KRb2CrF6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.850
_cell_length_b   10.612
_cell_length_c   10.612
_cell_angle_alpha   79.986
_cell_angle_beta   65.355
_cell_angle_gamma   65.355
_symmetry_Int_Tables_number   1
_cell_volume   823.397
_cell_formula_units_Z   5
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
  K  K0  1  0.500  0.000  0.000  1.0
  K  K1  1  0.263  0.825  0.649  1.0
  K  K2  1  0.088  0.649  0.175  1.0
  K  K3  1  0.737  0.175  0.351  1.0
  K  K4  1  0.912  0.351  0.825  1.0
  Rb  Rb5  1  0.750  0.500  0.500  1.0
  Rb  Rb6  1  0.250  0.500  0.500  1.0
  Rb  Rb7  1  0.619  0.894  0.318  1.0
  Rb  Rb8  1  0.514  0.318  0.106  1.0
  Rb  Rb9  1  0.832  0.106  0.682  1.0
  Rb  Rb10  1  0.938  0.682  0.894  1.0
  Rb  Rb11  1  0.381  0.106  0.682  1.0
  Rb  Rb12  1  0.486  0.682  0.894  1.0
  Rb  Rb13  1  0.168  0.894  0.318  1.0
  Rb  Rb14  1  0.062  0.318  0.106  1.0
  Cr  Cr15  1  0.000  0.000  0.000  1.0
  Cr  Cr16  1  0.804  0.791  0.601  1.0
  Cr  Cr17  1  0.595  0.601  0.209  1.0
  Cr  Cr18  1  0.196  0.209  0.399  1.0
  Cr  Cr19  1  0.405  0.399  0.791  1.0
  F  F20  1  0.937  0.937  0.189  1.0
  F  F21  1  0.874  0.189  0.063  1.0
  F  F22  1  0.063  0.063  0.811  1.0
  F  F23  1  0.126  0.811  0.937  1.0
  F  F24  1  0.784  0.000  0.000  1.0
  F  F25  1  0.216  0.000  0.000  1.0
  F  F26  1  0.672  0.880  0.777  1.0
  F  F27  1  0.552  0.777  0.120  1.0
  F  F28  1  0.328  0.120  0.223  1.0
  F  F29  1  0.448  0.223  0.880  1.0
  F  F30  1  0.847  0.613  0.693  1.0
  F  F31  1  0.460  0.693  0.387  1.0
  F  F32  1  0.153  0.387  0.307  1.0
  F  F33  1  0.540  0.307  0.613  1.0
  F  F34  1  0.936  0.701  0.426  1.0
  F  F35  1  0.637  0.426  0.299  1.0
  F  F36  1  0.064  0.299  0.574  1.0
  F  F37  1  0.363  0.574  0.701  1.0
  F  F38  1  0.759  0.969  0.513  1.0
  F  F39  1  0.728  0.513  0.031  1.0
  F  F40  1  0.241  0.031  0.487  1.0
  F  F41  1  0.272  0.487  0.969  1.0
  F  F42  1  0.584  0.795  0.603  1.0
  F  F43  1  0.378  0.603  0.205  1.0
  F  F44  1  0.982  0.205  0.397  1.0
  F  F45  1  0.187  0.397  0.795  1.0
  F  F46  1  0.416  0.205  0.397  1.0
  F  F47  1  0.622  0.397  0.795  1.0
  F  F48  1  0.018  0.795  0.603  1.0
  F  F49  1  0.813  0.603  0.205  1.0
[/CIF]
.