The material described by Rb2CaV2O7 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(2), one O(4), one O(6), two equivalent O(5), and three equivalent O(3) atoms. In the second Rb site, Rb(2) is bonded in a 10-coordinate geometry to one O(4), one O(5), one O(6), two equivalent O(1), two equivalent O(2), and three equivalent O(7) atoms. Ca(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form CaO6 octahedra that share corners with three equivalent V(1)O4 tetrahedra and corners with three equivalent V(2)O4 tetrahedra. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(2), one O(5), and one O(7) atom to form VO4 tetrahedra that share corners with three equivalent Ca(1)O6 octahedra and  a cornercorner with one V(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 11-46°. In the second V site, V(2) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form VO4 tetrahedra that share corners with three equivalent Ca(1)O6 octahedra and  a cornercorner with one V(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-43°. There are seven inequivalent O sites. In the first O site, O(7) is bonded in a 2-coordinate geometry to three equivalent Rb(2), one Ca(1), and one V(1) atom. In the second O site, O(1) is bonded in a distorted bent 120 degrees geometry to two equivalent Rb(2), one V(1), and one V(2) atom. In the third O site, O(2) is bonded in a 2-coordinate geometry to one Rb(1), two equivalent Rb(2), one Ca(1), and one V(1) atom. In the fourth O site, O(3) is bonded in a 2-coordinate geometry to three equivalent Rb(1), one Ca(1), and one V(2) atom. In the fifth O site, O(4) is bonded in a 2-coordinate geometry to one Rb(1), one Rb(2), one Ca(1), and one V(2) atom. In the sixth O site, O(5) is bonded in a 5-coordinate geometry to one Rb(2), two equivalent Rb(1), one Ca(1), and one V(1) atom. In the seventh O site, O(6) is bonded in a 2-coordinate geometry to one Rb(1), one Rb(2), one Ca(1), and one V(2) atom. is represented by the CIF card [CIF]
data_Rb2CaV2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.080
_cell_length_b   10.499
_cell_length_c   15.346
_cell_angle_alpha   63.613
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   877.459
_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  0.765  0.973  0.169  1.0
  Rb  Rb1  1  0.725  0.501  0.870  1.0
  Rb  Rb2  1  0.235  0.027  0.831  1.0
  Rb  Rb3  1  0.265  0.027  0.331  1.0
  Rb  Rb4  1  0.735  0.973  0.669  1.0
  Rb  Rb5  1  0.275  0.499  0.130  1.0
  Rb  Rb6  1  0.225  0.499  0.630  1.0
  Rb  Rb7  1  0.775  0.501  0.370  1.0
  Ca  Ca8  1  0.240  0.230  0.022  1.0
  Ca  Ca9  1  0.260  0.230  0.522  1.0
  Ca  Ca10  1  0.740  0.770  0.478  1.0
  Ca  Ca11  1  0.760  0.770  0.978  1.0
  V  V12  1  0.734  0.338  0.639  1.0
  V  V13  1  0.728  0.173  0.878  1.0
  V  V14  1  0.272  0.827  0.122  1.0
  V  V15  1  0.266  0.662  0.361  1.0
  V  V16  1  0.772  0.173  0.378  1.0
  V  V17  1  0.766  0.338  0.139  1.0
  V  V18  1  0.234  0.662  0.861  1.0
  V  V19  1  0.228  0.827  0.622  1.0
  O  O20  1  0.187  0.681  0.240  1.0
  O  O21  1  0.946  0.270  0.598  1.0
  O  O22  1  0.270  0.986  0.130  1.0
  O  O23  1  0.770  0.014  0.370  1.0
  O  O24  1  0.916  0.176  0.960  1.0
  O  O25  1  0.730  0.014  0.870  1.0
  O  O26  1  0.490  0.252  0.644  1.0
  O  O27  1  0.469  0.212  0.904  1.0
  O  O28  1  0.084  0.824  0.040  1.0
  O  O29  1  0.554  0.270  0.098  1.0
  O  O30  1  0.510  0.748  0.356  1.0
  O  O31  1  0.990  0.748  0.856  1.0
  O  O32  1  0.054  0.730  0.402  1.0
  O  O33  1  0.969  0.788  0.596  1.0
  O  O34  1  0.031  0.212  0.404  1.0
  O  O35  1  0.584  0.176  0.460  1.0
  O  O36  1  0.446  0.730  0.902  1.0
  O  O37  1  0.292  0.482  0.433  1.0
  O  O38  1  0.708  0.518  0.567  1.0
  O  O39  1  0.813  0.319  0.760  1.0
  O  O40  1  0.416  0.824  0.540  1.0
  O  O41  1  0.792  0.518  0.067  1.0
  O  O42  1  0.010  0.252  0.144  1.0
  O  O43  1  0.230  0.986  0.630  1.0
  O  O44  1  0.313  0.681  0.740  1.0
  O  O45  1  0.687  0.319  0.260  1.0
  O  O46  1  0.208  0.482  0.933  1.0
  O  O47  1  0.531  0.788  0.096  1.0
[/CIF]
.
The material described by Rb2CaV2O7 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(2), one O(4), one O(6), two equivalent O(5), and three equivalent O(3) atoms. In the second Rb site, Rb(2) is bonded in a 10-coordinate geometry to one O(4), one O(5), one O(6), two equivalent O(1), two equivalent O(2), and three equivalent O(7) atoms. Ca(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form CaO6 octahedra that share corners with three equivalent V(1)O4 tetrahedra and corners with three equivalent V(2)O4 tetrahedra. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(2), one O(5), and one O(7) atom to form VO4 tetrahedra that share corners with three equivalent Ca(1)O6 octahedra and  a cornercorner with one V(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 11-46°. In the second V site, V(2) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form VO4 tetrahedra that share corners with three equivalent Ca(1)O6 octahedra and  a cornercorner with one V(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-43°. There are seven inequivalent O sites. In the first O site, O(7) is bonded in a 2-coordinate geometry to three equivalent Rb(2), one Ca(1), and one V(1) atom. In the second O site, O(1) is bonded in a distorted bent 120 degrees geometry to two equivalent Rb(2), one V(1), and one V(2) atom. In the third O site, O(2) is bonded in a 2-coordinate geometry to one Rb(1), two equivalent Rb(2), one Ca(1), and one V(1) atom. In the fourth O site, O(3) is bonded in a 2-coordinate geometry to three equivalent Rb(1), one Ca(1), and one V(2) atom. In the fifth O site, O(4) is bonded in a 2-coordinate geometry to one Rb(1), one Rb(2), one Ca(1), and one V(2) atom. In the sixth O site, O(5) is bonded in a 5-coordinate geometry to one Rb(2), two equivalent Rb(1), one Ca(1), and one V(1) atom. In the seventh O site, O(6) is bonded in a 2-coordinate geometry to one Rb(1), one Rb(2), one Ca(1), and one V(2) atom. is represented by the CIF card [CIF]
data_Rb2CaV2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.080
_cell_length_b   10.499
_cell_length_c   15.346
_cell_angle_alpha   63.613
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   877.459
_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  0.765  0.973  0.169  1.0
  Rb  Rb1  1  0.725  0.501  0.870  1.0
  Rb  Rb2  1  0.235  0.027  0.831  1.0
  Rb  Rb3  1  0.265  0.027  0.331  1.0
  Rb  Rb4  1  0.735  0.973  0.669  1.0
  Rb  Rb5  1  0.275  0.499  0.130  1.0
  Rb  Rb6  1  0.225  0.499  0.630  1.0
  Rb  Rb7  1  0.775  0.501  0.370  1.0
  Ca  Ca8  1  0.240  0.230  0.022  1.0
  Ca  Ca9  1  0.260  0.230  0.522  1.0
  Ca  Ca10  1  0.740  0.770  0.478  1.0
  Ca  Ca11  1  0.760  0.770  0.978  1.0
  V  V12  1  0.734  0.338  0.639  1.0
  V  V13  1  0.728  0.173  0.878  1.0
  V  V14  1  0.272  0.827  0.122  1.0
  V  V15  1  0.266  0.662  0.361  1.0
  V  V16  1  0.772  0.173  0.378  1.0
  V  V17  1  0.766  0.338  0.139  1.0
  V  V18  1  0.234  0.662  0.861  1.0
  V  V19  1  0.228  0.827  0.622  1.0
  O  O20  1  0.187  0.681  0.240  1.0
  O  O21  1  0.946  0.270  0.598  1.0
  O  O22  1  0.270  0.986  0.130  1.0
  O  O23  1  0.770  0.014  0.370  1.0
  O  O24  1  0.916  0.176  0.960  1.0
  O  O25  1  0.730  0.014  0.870  1.0
  O  O26  1  0.490  0.252  0.644  1.0
  O  O27  1  0.469  0.212  0.904  1.0
  O  O28  1  0.084  0.824  0.040  1.0
  O  O29  1  0.554  0.270  0.098  1.0
  O  O30  1  0.510  0.748  0.356  1.0
  O  O31  1  0.990  0.748  0.856  1.0
  O  O32  1  0.054  0.730  0.402  1.0
  O  O33  1  0.969  0.788  0.596  1.0
  O  O34  1  0.031  0.212  0.404  1.0
  O  O35  1  0.584  0.176  0.460  1.0
  O  O36  1  0.446  0.730  0.902  1.0
  O  O37  1  0.292  0.482  0.433  1.0
  O  O38  1  0.708  0.518  0.567  1.0
  O  O39  1  0.813  0.319  0.760  1.0
  O  O40  1  0.416  0.824  0.540  1.0
  O  O41  1  0.792  0.518  0.067  1.0
  O  O42  1  0.010  0.252  0.144  1.0
  O  O43  1  0.230  0.986  0.630  1.0
  O  O44  1  0.313  0.681  0.740  1.0
  O  O45  1  0.687  0.319  0.260  1.0
  O  O46  1  0.208  0.482  0.933  1.0
  O  O47  1  0.531  0.788  0.096  1.0
[/CIF]
.