The structure described by Rb2Cr2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 8-coordinate geometry to one O(3), one O(4), one O(6), one O(7), two equivalent O(1), and two equivalent O(2) atoms. In the second Rb site, Rb(2) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form corner-sharing CrO4 tetrahedra. In the second Cr site, Cr(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form corner-sharing CrO4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to one Rb(2), two equivalent Rb(1), and one Cr(2) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Rb(2), two equivalent Rb(1), and one Cr(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Rb(1), one Rb(2), and one Cr(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Rb(1), one Cr(1), and one Cr(2) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to two equivalent Rb(2) and one Cr(1) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Rb(1), two equivalent Rb(2), and one Cr(1) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Rb(1), two equivalent Rb(2), and one Cr(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Rb2Cr2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.592
_cell_length_b   7.663
_cell_length_c   15.214
_cell_angle_alpha   63.758
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   793.897
_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
  Rb  Rb0  1  0.274  0.061  0.637  1.0
  Rb  Rb1  1  0.226  0.061  0.137  1.0
  Rb  Rb2  1  0.118  0.515  0.842  1.0
  Rb  Rb3  1  0.726  0.939  0.363  1.0
  Rb  Rb4  1  0.618  0.485  0.658  1.0
  Rb  Rb5  1  0.882  0.485  0.158  1.0
  Rb  Rb6  1  0.774  0.939  0.863  1.0
  Rb  Rb7  1  0.382  0.515  0.342  1.0
  Cr  Cr8  1  0.663  0.399  0.920  1.0
  Cr  Cr9  1  0.786  0.006  0.610  1.0
  Cr  Cr10  1  0.163  0.601  0.580  1.0
  Cr  Cr11  1  0.837  0.399  0.420  1.0
  Cr  Cr12  1  0.214  0.994  0.390  1.0
  Cr  Cr13  1  0.286  0.994  0.890  1.0
  Cr  Cr14  1  0.337  0.601  0.080  1.0
  Cr  Cr15  1  0.714  0.006  0.110  1.0
  O  O16  1  0.914  0.855  0.695  1.0
  O  O17  1  0.152  0.895  0.842  1.0
  O  O18  1  0.675  0.896  0.559  1.0
  O  O19  1  0.580  0.189  0.022  1.0
  O  O20  1  0.348  0.895  0.342  1.0
  O  O21  1  0.498  0.466  0.142  1.0
  O  O22  1  0.825  0.896  0.059  1.0
  O  O23  1  0.723  0.327  0.351  1.0
  O  O24  1  0.420  0.811  0.978  1.0
  O  O25  1  0.777  0.327  0.851  1.0
  O  O26  1  0.208  0.481  0.042  1.0
  O  O27  1  0.652  0.105  0.658  1.0
  O  O28  1  0.502  0.534  0.858  1.0
  O  O29  1  0.002  0.466  0.642  1.0
  O  O30  1  0.586  0.855  0.195  1.0
  O  O31  1  0.708  0.519  0.458  1.0
  O  O32  1  0.223  0.673  0.149  1.0
  O  O33  1  0.175  0.104  0.941  1.0
  O  O34  1  0.292  0.481  0.542  1.0
  O  O35  1  0.920  0.189  0.522  1.0
  O  O36  1  0.998  0.534  0.358  1.0
  O  O37  1  0.414  0.145  0.805  1.0
  O  O38  1  0.086  0.145  0.305  1.0
  O  O39  1  0.792  0.519  0.958  1.0
  O  O40  1  0.325  0.104  0.441  1.0
  O  O41  1  0.080  0.811  0.478  1.0
  O  O42  1  0.277  0.673  0.649  1.0
  O  O43  1  0.848  0.105  0.158  1.0
[/CIF]
.
The structure described by Rb2Cr2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 8-coordinate geometry to one O(3), one O(4), one O(6), one O(7), two equivalent O(1), and two equivalent O(2) atoms. In the second Rb site, Rb(2) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form corner-sharing CrO4 tetrahedra. In the second Cr site, Cr(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form corner-sharing CrO4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to one Rb(2), two equivalent Rb(1), and one Cr(2) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Rb(2), two equivalent Rb(1), and one Cr(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Rb(1), one Rb(2), and one Cr(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Rb(1), one Cr(1), and one Cr(2) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to two equivalent Rb(2) and one Cr(1) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Rb(1), two equivalent Rb(2), and one Cr(1) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Rb(1), two equivalent Rb(2), and one Cr(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Rb2Cr2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.592
_cell_length_b   7.663
_cell_length_c   15.214
_cell_angle_alpha   63.758
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   793.897
_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
  Rb  Rb0  1  0.274  0.061  0.637  1.0
  Rb  Rb1  1  0.226  0.061  0.137  1.0
  Rb  Rb2  1  0.118  0.515  0.842  1.0
  Rb  Rb3  1  0.726  0.939  0.363  1.0
  Rb  Rb4  1  0.618  0.485  0.658  1.0
  Rb  Rb5  1  0.882  0.485  0.158  1.0
  Rb  Rb6  1  0.774  0.939  0.863  1.0
  Rb  Rb7  1  0.382  0.515  0.342  1.0
  Cr  Cr8  1  0.663  0.399  0.920  1.0
  Cr  Cr9  1  0.786  0.006  0.610  1.0
  Cr  Cr10  1  0.163  0.601  0.580  1.0
  Cr  Cr11  1  0.837  0.399  0.420  1.0
  Cr  Cr12  1  0.214  0.994  0.390  1.0
  Cr  Cr13  1  0.286  0.994  0.890  1.0
  Cr  Cr14  1  0.337  0.601  0.080  1.0
  Cr  Cr15  1  0.714  0.006  0.110  1.0
  O  O16  1  0.914  0.855  0.695  1.0
  O  O17  1  0.152  0.895  0.842  1.0
  O  O18  1  0.675  0.896  0.559  1.0
  O  O19  1  0.580  0.189  0.022  1.0
  O  O20  1  0.348  0.895  0.342  1.0
  O  O21  1  0.498  0.466  0.142  1.0
  O  O22  1  0.825  0.896  0.059  1.0
  O  O23  1  0.723  0.327  0.351  1.0
  O  O24  1  0.420  0.811  0.978  1.0
  O  O25  1  0.777  0.327  0.851  1.0
  O  O26  1  0.208  0.481  0.042  1.0
  O  O27  1  0.652  0.105  0.658  1.0
  O  O28  1  0.502  0.534  0.858  1.0
  O  O29  1  0.002  0.466  0.642  1.0
  O  O30  1  0.586  0.855  0.195  1.0
  O  O31  1  0.708  0.519  0.458  1.0
  O  O32  1  0.223  0.673  0.149  1.0
  O  O33  1  0.175  0.104  0.941  1.0
  O  O34  1  0.292  0.481  0.542  1.0
  O  O35  1  0.920  0.189  0.522  1.0
  O  O36  1  0.998  0.534  0.358  1.0
  O  O37  1  0.414  0.145  0.805  1.0
  O  O38  1  0.086  0.145  0.305  1.0
  O  O39  1  0.792  0.519  0.958  1.0
  O  O40  1  0.325  0.104  0.441  1.0
  O  O41  1  0.080  0.811  0.478  1.0
  O  O42  1  0.277  0.673  0.649  1.0
  O  O43  1  0.848  0.105  0.158  1.0
[/CIF]
.