The material structure described by Na2Cr2O7H2 crystallizes in the monoclinic P2_1 space group. The structure consists of eight 1333-74-0 atoms inside a Na2Cr2O7 framework. In the Na2Cr2O7 framework, there are four inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form distorted NaO4 trigonal pyramids that share  a cornercorner with one Cr(1)O4 tetrahedra,  a cornercorner with one Cr(2)O4 tetrahedra,  a cornercorner with one Cr(4)O4 tetrahedra, and corners with two equivalent Cr(3)O4 tetrahedra. In the second Na site, Na(2) is bonded in a distorted see-saw-like geometry to one O(1), one O(13), one O(14), and one O(5) atom. In the third Na site, Na(3) is bonded in a distorted see-saw-like geometry to one O(10), one O(13), one O(2), and one O(8) atom. In the fourth Na site, Na(4) is bonded to one O(11), one O(12), one O(7), and one O(9) atom to form distorted NaO4 trigonal pyramids that share  a cornercorner with one Cr(1)O4 tetrahedra,  a cornercorner with one Cr(3)O4 tetrahedra, and corners with three equivalent Cr(4)O4 tetrahedra. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(2), one O(3), one O(8), and one O(9) atom to form CrO4 tetrahedra that share  a cornercorner with one Cr(4)O4 tetrahedra,  a cornercorner with one Na(1)O4 trigonal pyramid, and  a cornercorner with one Na(4)O4 trigonal pyramid. In the second Cr site, Cr(2) is bonded to one O(13), one O(14), one O(4), and one O(5) atom to form CrO4 tetrahedra that share  a cornercorner with one Cr(3)O4 tetrahedra and  a cornercorner with one Na(1)O4 trigonal pyramid. In the third Cr site, Cr(3) is bonded to one O(1), one O(10), one O(11), and one O(4) atom to form CrO4 tetrahedra that share  a cornercorner with one Cr(2)O4 tetrahedra,  a cornercorner with one Na(4)O4 trigonal pyramid, and corners with two equivalent Na(1)O4 trigonal pyramids. In the fourth Cr site, Cr(4) is bonded to one O(12), one O(6), one O(7), and one O(9) atom to form CrO4 tetrahedra that share  a cornercorner with one Cr(1)O4 tetrahedra,  a cornercorner with one Na(1)O4 trigonal pyramid, and corners with three equivalent Na(4)O4 trigonal pyramids. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Na(1), one Na(2), and one Cr(3) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Na(3) and one Cr(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Na(1) and one Cr(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Na(1), one Cr(2), and one Cr(3) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Na(2) and one Cr(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Na(1) and one Cr(4) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Na(4) and one Cr(4) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Na(3) and one Cr(1) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Na(4), one Cr(1), and one Cr(4) atom. In the tenth O site, O(10) is bonded in a distorted bent 120 degrees geometry to one Na(3) and one Cr(3) atom. In the eleventh O site, O(11) is bonded in a distorted bent 150 degrees geometry to one Na(4) and one Cr(3) atom. In the twelfth O site, O(12) is bonded in a distorted bent 150 degrees geometry to one Na(4) and one Cr(4) atom. In the thirteenth O site, O(13) is bonded in a trigonal planar geometry to one Na(2), one Na(3), and one Cr(2) atom. In the fourteenth O site, O(14) is bonded in a bent 150 degrees geometry to one Na(2) and one Cr(2) atom. is represented by the CIF file [CIF]
data_Na2Cr2H2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.510
_cell_length_b   6.342
_cell_length_c   13.523
_cell_angle_alpha   88.927
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   901.202
_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
  Na  Na0  1  0.838  0.352  0.230  1.0
  Na  Na1  1  0.338  0.648  0.770  1.0
  Na  Na2  1  0.322  0.322  0.011  1.0
  Na  Na3  1  0.822  0.678  0.989  1.0
  Na  Na4  1  0.339  0.932  0.235  1.0
  Na  Na5  1  0.839  0.068  0.765  1.0
  Na  Na6  1  0.879  0.833  0.472  1.0
  Na  Na7  1  0.379  0.167  0.528  1.0
  Cr  Cr8  1  0.507  0.436  0.333  1.0
  Cr  Cr9  1  0.007  0.564  0.667  1.0
  Cr  Cr10  1  0.493  0.847  0.005  1.0
  Cr  Cr11  1  0.993  0.153  0.995  1.0
  Cr  Cr12  1  0.994  0.856  0.191  1.0
  Cr  Cr13  1  0.494  0.144  0.809  1.0
  Cr  Cr14  1  0.552  0.661  0.542  1.0
  Cr  Cr15  1  0.052  0.339  0.458  1.0
  H  H16  1  0.715  0.972  0.314  1.0
  H  H17  1  0.215  0.028  0.686  1.0
  H  H18  1  0.723  0.675  0.797  1.0
  H  H19  1  0.223  0.325  0.203  1.0
  H  H20  1  0.235  0.844  0.428  1.0
  H  H21  1  0.735  0.156  0.572  1.0
  H  H22  1  0.683  0.334  0.066  1.0
  H  H23  1  0.183  0.666  0.934  1.0
  O  O24  1  0.902  0.668  0.150  1.0
  O  O25  1  0.402  0.332  0.850  1.0
  O  O26  1  0.413  0.615  0.285  1.0
  O  O27  1  0.913  0.385  0.715  1.0
  O  O28  1  0.654  0.480  0.296  1.0
  O  O29  1  0.154  0.520  0.704  1.0
  O  O30  1  0.959  0.099  0.123  1.0
  O  O31  1  0.459  0.901  0.877  1.0
  O  O32  1  0.644  0.877  0.024  1.0
  O  O33  1  0.144  0.123  0.976  1.0
  O  O34  1  0.984  0.376  0.350  1.0
  O  O35  1  0.484  0.624  0.650  1.0
  O  O36  1  0.508  0.884  0.490  1.0
  O  O37  1  0.008  0.116  0.510  1.0
  O  O38  1  0.960  0.800  0.697  1.0
  O  O39  1  0.460  0.200  0.303  1.0
  O  O40  1  0.002  0.552  0.535  1.0
  O  O41  1  0.502  0.448  0.465  1.0
  O  O42  1  0.143  0.797  0.174  1.0
  O  O43  1  0.643  0.203  0.826  1.0
  O  O44  1  0.966  0.896  0.308  1.0
  O  O45  1  0.466  0.104  0.692  1.0
  O  O46  1  0.707  0.659  0.553  1.0
  O  O47  1  0.207  0.341  0.447  1.0
  O  O48  1  0.913  0.986  0.927  1.0
  O  O49  1  0.413  0.014  0.073  1.0
  O  O50  1  0.451  0.606  0.031  1.0
  O  O51  1  0.951  0.394  0.969  1.0
[/CIF]
.
The material structure described by Na2Cr2O7H2 crystallizes in the monoclinic P2_1 space group. The structure consists of eight 1333-74-0 atoms inside a Na2Cr2O7 framework. In the Na2Cr2O7 framework, there are four inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form distorted NaO4 trigonal pyramids that share  a cornercorner with one Cr(1)O4 tetrahedra,  a cornercorner with one Cr(2)O4 tetrahedra,  a cornercorner with one Cr(4)O4 tetrahedra, and corners with two equivalent Cr(3)O4 tetrahedra. In the second Na site, Na(2) is bonded in a distorted see-saw-like geometry to one O(1), one O(13), one O(14), and one O(5) atom. In the third Na site, Na(3) is bonded in a distorted see-saw-like geometry to one O(10), one O(13), one O(2), and one O(8) atom. In the fourth Na site, Na(4) is bonded to one O(11), one O(12), one O(7), and one O(9) atom to form distorted NaO4 trigonal pyramids that share  a cornercorner with one Cr(1)O4 tetrahedra,  a cornercorner with one Cr(3)O4 tetrahedra, and corners with three equivalent Cr(4)O4 tetrahedra. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(2), one O(3), one O(8), and one O(9) atom to form CrO4 tetrahedra that share  a cornercorner with one Cr(4)O4 tetrahedra,  a cornercorner with one Na(1)O4 trigonal pyramid, and  a cornercorner with one Na(4)O4 trigonal pyramid. In the second Cr site, Cr(2) is bonded to one O(13), one O(14), one O(4), and one O(5) atom to form CrO4 tetrahedra that share  a cornercorner with one Cr(3)O4 tetrahedra and  a cornercorner with one Na(1)O4 trigonal pyramid. In the third Cr site, Cr(3) is bonded to one O(1), one O(10), one O(11), and one O(4) atom to form CrO4 tetrahedra that share  a cornercorner with one Cr(2)O4 tetrahedra,  a cornercorner with one Na(4)O4 trigonal pyramid, and corners with two equivalent Na(1)O4 trigonal pyramids. In the fourth Cr site, Cr(4) is bonded to one O(12), one O(6), one O(7), and one O(9) atom to form CrO4 tetrahedra that share  a cornercorner with one Cr(1)O4 tetrahedra,  a cornercorner with one Na(1)O4 trigonal pyramid, and corners with three equivalent Na(4)O4 trigonal pyramids. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Na(1), one Na(2), and one Cr(3) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Na(3) and one Cr(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Na(1) and one Cr(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Na(1), one Cr(2), and one Cr(3) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Na(2) and one Cr(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Na(1) and one Cr(4) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Na(4) and one Cr(4) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Na(3) and one Cr(1) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Na(4), one Cr(1), and one Cr(4) atom. In the tenth O site, O(10) is bonded in a distorted bent 120 degrees geometry to one Na(3) and one Cr(3) atom. In the eleventh O site, O(11) is bonded in a distorted bent 150 degrees geometry to one Na(4) and one Cr(3) atom. In the twelfth O site, O(12) is bonded in a distorted bent 150 degrees geometry to one Na(4) and one Cr(4) atom. In the thirteenth O site, O(13) is bonded in a trigonal planar geometry to one Na(2), one Na(3), and one Cr(2) atom. In the fourteenth O site, O(14) is bonded in a bent 150 degrees geometry to one Na(2) and one Cr(2) atom. is represented by the CIF file [CIF]
data_Na2Cr2H2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.510
_cell_length_b   6.342
_cell_length_c   13.523
_cell_angle_alpha   88.927
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   901.202
_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
  Na  Na0  1  0.838  0.352  0.230  1.0
  Na  Na1  1  0.338  0.648  0.770  1.0
  Na  Na2  1  0.322  0.322  0.011  1.0
  Na  Na3  1  0.822  0.678  0.989  1.0
  Na  Na4  1  0.339  0.932  0.235  1.0
  Na  Na5  1  0.839  0.068  0.765  1.0
  Na  Na6  1  0.879  0.833  0.472  1.0
  Na  Na7  1  0.379  0.167  0.528  1.0
  Cr  Cr8  1  0.507  0.436  0.333  1.0
  Cr  Cr9  1  0.007  0.564  0.667  1.0
  Cr  Cr10  1  0.493  0.847  0.005  1.0
  Cr  Cr11  1  0.993  0.153  0.995  1.0
  Cr  Cr12  1  0.994  0.856  0.191  1.0
  Cr  Cr13  1  0.494  0.144  0.809  1.0
  Cr  Cr14  1  0.552  0.661  0.542  1.0
  Cr  Cr15  1  0.052  0.339  0.458  1.0
  H  H16  1  0.715  0.972  0.314  1.0
  H  H17  1  0.215  0.028  0.686  1.0
  H  H18  1  0.723  0.675  0.797  1.0
  H  H19  1  0.223  0.325  0.203  1.0
  H  H20  1  0.235  0.844  0.428  1.0
  H  H21  1  0.735  0.156  0.572  1.0
  H  H22  1  0.683  0.334  0.066  1.0
  H  H23  1  0.183  0.666  0.934  1.0
  O  O24  1  0.902  0.668  0.150  1.0
  O  O25  1  0.402  0.332  0.850  1.0
  O  O26  1  0.413  0.615  0.285  1.0
  O  O27  1  0.913  0.385  0.715  1.0
  O  O28  1  0.654  0.480  0.296  1.0
  O  O29  1  0.154  0.520  0.704  1.0
  O  O30  1  0.959  0.099  0.123  1.0
  O  O31  1  0.459  0.901  0.877  1.0
  O  O32  1  0.644  0.877  0.024  1.0
  O  O33  1  0.144  0.123  0.976  1.0
  O  O34  1  0.984  0.376  0.350  1.0
  O  O35  1  0.484  0.624  0.650  1.0
  O  O36  1  0.508  0.884  0.490  1.0
  O  O37  1  0.008  0.116  0.510  1.0
  O  O38  1  0.960  0.800  0.697  1.0
  O  O39  1  0.460  0.200  0.303  1.0
  O  O40  1  0.002  0.552  0.535  1.0
  O  O41  1  0.502  0.448  0.465  1.0
  O  O42  1  0.143  0.797  0.174  1.0
  O  O43  1  0.643  0.203  0.826  1.0
  O  O44  1  0.966  0.896  0.308  1.0
  O  O45  1  0.466  0.104  0.692  1.0
  O  O46  1  0.707  0.659  0.553  1.0
  O  O47  1  0.207  0.341  0.447  1.0
  O  O48  1  0.913  0.986  0.927  1.0
  O  O49  1  0.413  0.014  0.073  1.0
  O  O50  1  0.451  0.606  0.031  1.0
  O  O51  1  0.951  0.394  0.969  1.0
[/CIF]
.