The compound described by K2Cr4O13 crystallizes in the monoclinic Pc space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 11-coordinate geometry to one O(1), one O(10), one O(11), one O(12), one O(13), one O(4), one O(7), two equivalent O(3), and two equivalent O(5) atoms. In the second K site, K(2) is bonded in a 8-coordinate geometry to one O(1), one O(11), one O(3), one O(4), one O(8), one O(9), and two equivalent O(13) atoms. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form corner-sharing CrO4 tetrahedra. In the second Cr site, Cr(2) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form corner-sharing CrO4 tetrahedra. In the third Cr site, Cr(3) is bonded to one O(12), one O(7), one O(8), and one O(9) atom to form corner-sharing CrO4 tetrahedra. In the fourth Cr site, Cr(4) is bonded to one O(10), one O(11), one O(12), and one O(13) atom to form corner-sharing CrO4 tetrahedra. There are thirteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one Cr(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Cr(1) and one Cr(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), and one Cr(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one Cr(1) atom. In the fifth O site, O(5) is bonded in a single-bond geometry to two equivalent K(1) and one Cr(2) atom. In the sixth O site, O(6) is bonded in a single-bond geometry to one Cr(2) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one K(1), one Cr(2), and one Cr(3) atom. In the eighth O site, O(8) is bonded in a single-bond geometry to one K(2) and one Cr(3) atom. In the ninth O site, O(9) is bonded in a single-bond geometry to one K(2) and one Cr(3) atom. In the tenth O site, O(10) is bonded in a distorted single-bond geometry to one K(1) and one Cr(4) atom. In the eleventh O site, O(11) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one Cr(4) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one K(1), one Cr(3), and one Cr(4) atom. In the thirteenth O site, O(13) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), and one Cr(4) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_K2Cr4O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.702
_cell_length_b   8.943
_cell_length_c   9.554
_cell_angle_alpha   87.495
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   657.368
_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
  K  K0  1  0.594  0.803  0.757  1.0
  K  K1  1  0.406  0.803  0.257  1.0
  K  K2  1  0.104  0.544  0.896  1.0
  K  K3  1  0.896  0.544  0.396  1.0
  Cr  Cr4  1  0.572  0.515  0.032  1.0
  Cr  Cr5  1  0.428  0.515  0.532  1.0
  Cr  Cr6  1  0.566  0.172  0.987  1.0
  Cr  Cr7  1  0.434  0.172  0.487  1.0
  Cr  Cr8  1  0.893  0.181  0.756  1.0
  Cr  Cr9  1  0.107  0.181  0.256  1.0
  Cr  Cr10  1  0.070  0.858  0.632  1.0
  Cr  Cr11  1  0.930  0.858  0.132  1.0
  O  O12  1  0.741  0.532  0.932  1.0
  O  O13  1  0.259  0.532  0.432  1.0
  O  O14  1  0.457  0.342  0.992  1.0
  O  O15  1  0.543  0.342  0.492  1.0
  O  O16  1  0.439  0.655  1.000  1.0
  O  O17  1  0.561  0.655  0.500  1.0
  O  O18  1  0.627  0.511  0.196  1.0
  O  O19  1  0.373  0.511  0.696  1.0
  O  O20  1  0.431  0.036  0.004  1.0
  O  O21  1  0.569  0.036  0.504  1.0
  O  O22  1  0.701  0.163  0.114  1.0
  O  O23  1  0.299  0.163  0.614  1.0
  O  O24  1  0.678  0.160  0.825  1.0
  O  O25  1  0.322  0.160  0.325  1.0
  O  O26  1  0.897  0.329  0.655  1.0
  O  O27  1  0.103  0.329  0.155  1.0
  O  O28  1  0.028  0.202  0.880  1.0
  O  O29  1  0.972  0.202  0.380  1.0
  O  O30  1  0.151  0.871  0.474  1.0
  O  O31  1  0.849  0.871  0.974  1.0
  O  O32  1  0.225  0.836  0.746  1.0
  O  O33  1  0.775  0.836  0.246  1.0
  O  O34  1  0.938  0.023  0.665  1.0
  O  O35  1  0.062  0.023  0.165  1.0
  O  O36  1  0.940  0.713  0.647  1.0
  O  O37  1  0.060  0.713  0.147  1.0
[/CIF]
.
The compound described by K2Cr4O13 crystallizes in the monoclinic Pc space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 11-coordinate geometry to one O(1), one O(10), one O(11), one O(12), one O(13), one O(4), one O(7), two equivalent O(3), and two equivalent O(5) atoms. In the second K site, K(2) is bonded in a 8-coordinate geometry to one O(1), one O(11), one O(3), one O(4), one O(8), one O(9), and two equivalent O(13) atoms. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form corner-sharing CrO4 tetrahedra. In the second Cr site, Cr(2) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form corner-sharing CrO4 tetrahedra. In the third Cr site, Cr(3) is bonded to one O(12), one O(7), one O(8), and one O(9) atom to form corner-sharing CrO4 tetrahedra. In the fourth Cr site, Cr(4) is bonded to one O(10), one O(11), one O(12), and one O(13) atom to form corner-sharing CrO4 tetrahedra. There are thirteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one Cr(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Cr(1) and one Cr(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), and one Cr(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one Cr(1) atom. In the fifth O site, O(5) is bonded in a single-bond geometry to two equivalent K(1) and one Cr(2) atom. In the sixth O site, O(6) is bonded in a single-bond geometry to one Cr(2) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one K(1), one Cr(2), and one Cr(3) atom. In the eighth O site, O(8) is bonded in a single-bond geometry to one K(2) and one Cr(3) atom. In the ninth O site, O(9) is bonded in a single-bond geometry to one K(2) and one Cr(3) atom. In the tenth O site, O(10) is bonded in a distorted single-bond geometry to one K(1) and one Cr(4) atom. In the eleventh O site, O(11) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one Cr(4) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one K(1), one Cr(3), and one Cr(4) atom. In the thirteenth O site, O(13) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), and one Cr(4) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_K2Cr4O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.702
_cell_length_b   8.943
_cell_length_c   9.554
_cell_angle_alpha   87.495
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   657.368
_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
  K  K0  1  0.594  0.803  0.757  1.0
  K  K1  1  0.406  0.803  0.257  1.0
  K  K2  1  0.104  0.544  0.896  1.0
  K  K3  1  0.896  0.544  0.396  1.0
  Cr  Cr4  1  0.572  0.515  0.032  1.0
  Cr  Cr5  1  0.428  0.515  0.532  1.0
  Cr  Cr6  1  0.566  0.172  0.987  1.0
  Cr  Cr7  1  0.434  0.172  0.487  1.0
  Cr  Cr8  1  0.893  0.181  0.756  1.0
  Cr  Cr9  1  0.107  0.181  0.256  1.0
  Cr  Cr10  1  0.070  0.858  0.632  1.0
  Cr  Cr11  1  0.930  0.858  0.132  1.0
  O  O12  1  0.741  0.532  0.932  1.0
  O  O13  1  0.259  0.532  0.432  1.0
  O  O14  1  0.457  0.342  0.992  1.0
  O  O15  1  0.543  0.342  0.492  1.0
  O  O16  1  0.439  0.655  1.000  1.0
  O  O17  1  0.561  0.655  0.500  1.0
  O  O18  1  0.627  0.511  0.196  1.0
  O  O19  1  0.373  0.511  0.696  1.0
  O  O20  1  0.431  0.036  0.004  1.0
  O  O21  1  0.569  0.036  0.504  1.0
  O  O22  1  0.701  0.163  0.114  1.0
  O  O23  1  0.299  0.163  0.614  1.0
  O  O24  1  0.678  0.160  0.825  1.0
  O  O25  1  0.322  0.160  0.325  1.0
  O  O26  1  0.897  0.329  0.655  1.0
  O  O27  1  0.103  0.329  0.155  1.0
  O  O28  1  0.028  0.202  0.880  1.0
  O  O29  1  0.972  0.202  0.380  1.0
  O  O30  1  0.151  0.871  0.474  1.0
  O  O31  1  0.849  0.871  0.974  1.0
  O  O32  1  0.225  0.836  0.746  1.0
  O  O33  1  0.775  0.836  0.246  1.0
  O  O34  1  0.938  0.023  0.665  1.0
  O  O35  1  0.062  0.023  0.165  1.0
  O  O36  1  0.940  0.713  0.647  1.0
  O  O37  1  0.060  0.713  0.147  1.0
[/CIF]
.