The crystal structure described by Na2Mo2O7 crystallizes in the orthorhombic Cmce space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(3), two equivalent O(4), and two equivalent O(5) atoms to form distorted NaO6 pentagonal pyramids that share corners with three equivalent Mo(1)O4 tetrahedra and edges with two equivalent Na(2)O6 octahedra. In the second Na site, Na(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form NaO6 octahedra that share corners with four equivalent Mo(1)O4 tetrahedra, edges with two equivalent Na(2)O6 octahedra, and edges with two equivalent Na(1)O6 pentagonal pyramids. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(1), one O(2), and two equivalent O(5) atoms to form MoO4 tetrahedra that share corners with four equivalent Na(2)O6 octahedra and corners with three equivalent Na(1)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 51-60°. In the second Mo site, Mo(2) is bonded in a 6-coordinate geometry to two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), two equivalent Na(2), and one Mo(1) atom to form distorted edge-sharing ONa3Mo trigonal pyramids. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Na(2) and one Mo(1) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Na(1) and two equivalent Mo(2) atoms. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one Mo(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Na(1), one Mo(1), and one Mo(2) atom. is represented by the CIF card [CIF]
data_Na2Mo2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.899
_cell_length_b   6.899
_cell_length_c   14.695
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   117.326
_symmetry_Int_Tables_number   1
_cell_volume   621.306
_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  0.319  0.681  0.345  1.0
  Na  Na1  1  0.181  0.819  0.845  1.0
  Na  Na2  1  0.681  0.319  0.655  1.0
  Na  Na3  1  0.819  0.181  0.155  1.0
  Na  Na4  1  0.247  0.247  0.000  1.0
  Na  Na5  1  0.253  0.253  0.500  1.0
  Na  Na6  1  0.753  0.753  0.000  1.0
  Na  Na7  1  0.747  0.747  0.500  1.0
  Mo  Mo8  1  0.247  0.753  0.084  1.0
  Mo  Mo9  1  0.253  0.747  0.584  1.0
  Mo  Mo10  1  0.753  0.247  0.916  1.0
  Mo  Mo11  1  0.747  0.253  0.416  1.0
  Mo  Mo12  1  0.331  0.169  0.250  1.0
  Mo  Mo13  1  0.169  0.331  0.750  1.0
  Mo  Mo14  1  0.669  0.831  0.750  1.0
  Mo  Mo15  1  0.831  0.669  0.250  1.0
  O  O16  1  0.361  0.639  0.501  1.0
  O  O17  1  0.139  0.861  0.001  1.0
  O  O18  1  0.639  0.361  0.499  1.0
  O  O19  1  0.861  0.139  0.999  1.0
  O  O20  1  0.377  0.623  0.029  1.0
  O  O21  1  0.123  0.877  0.529  1.0
  O  O22  1  0.623  0.377  0.971  1.0
  O  O23  1  0.877  0.123  0.471  1.0
  O  O24  1  0.121  0.879  0.282  1.0
  O  O25  1  0.379  0.621  0.782  1.0
  O  O26  1  0.879  0.121  0.718  1.0
  O  O27  1  0.621  0.379  0.218  1.0
  O  O28  1  0.709  0.690  0.662  1.0
  O  O29  1  0.791  0.810  0.162  1.0
  O  O30  1  0.690  0.709  0.338  1.0
  O  O31  1  0.810  0.791  0.838  1.0
  O  O32  1  0.933  0.470  0.345  1.0
  O  O33  1  0.567  0.030  0.845  1.0
  O  O34  1  0.470  0.933  0.655  1.0
  O  O35  1  0.030  0.567  0.155  1.0
  O  O36  1  0.067  0.530  0.655  1.0
  O  O37  1  0.433  0.970  0.155  1.0
  O  O38  1  0.530  0.067  0.345  1.0
  O  O39  1  0.970  0.433  0.845  1.0
  O  O40  1  0.190  0.209  0.162  1.0
  O  O41  1  0.310  0.291  0.662  1.0
  O  O42  1  0.209  0.190  0.838  1.0
  O  O43  1  0.291  0.310  0.338  1.0
[/CIF]
.
The crystal structure described by Na2Mo2O7 crystallizes in the orthorhombic Cmce space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(3), two equivalent O(4), and two equivalent O(5) atoms to form distorted NaO6 pentagonal pyramids that share corners with three equivalent Mo(1)O4 tetrahedra and edges with two equivalent Na(2)O6 octahedra. In the second Na site, Na(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form NaO6 octahedra that share corners with four equivalent Mo(1)O4 tetrahedra, edges with two equivalent Na(2)O6 octahedra, and edges with two equivalent Na(1)O6 pentagonal pyramids. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(1), one O(2), and two equivalent O(5) atoms to form MoO4 tetrahedra that share corners with four equivalent Na(2)O6 octahedra and corners with three equivalent Na(1)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 51-60°. In the second Mo site, Mo(2) is bonded in a 6-coordinate geometry to two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), two equivalent Na(2), and one Mo(1) atom to form distorted edge-sharing ONa3Mo trigonal pyramids. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Na(2) and one Mo(1) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Na(1) and two equivalent Mo(2) atoms. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one Mo(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Na(1), one Mo(1), and one Mo(2) atom. is represented by the CIF card [CIF]
data_Na2Mo2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.899
_cell_length_b   6.899
_cell_length_c   14.695
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   117.326
_symmetry_Int_Tables_number   1
_cell_volume   621.306
_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  0.319  0.681  0.345  1.0
  Na  Na1  1  0.181  0.819  0.845  1.0
  Na  Na2  1  0.681  0.319  0.655  1.0
  Na  Na3  1  0.819  0.181  0.155  1.0
  Na  Na4  1  0.247  0.247  0.000  1.0
  Na  Na5  1  0.253  0.253  0.500  1.0
  Na  Na6  1  0.753  0.753  0.000  1.0
  Na  Na7  1  0.747  0.747  0.500  1.0
  Mo  Mo8  1  0.247  0.753  0.084  1.0
  Mo  Mo9  1  0.253  0.747  0.584  1.0
  Mo  Mo10  1  0.753  0.247  0.916  1.0
  Mo  Mo11  1  0.747  0.253  0.416  1.0
  Mo  Mo12  1  0.331  0.169  0.250  1.0
  Mo  Mo13  1  0.169  0.331  0.750  1.0
  Mo  Mo14  1  0.669  0.831  0.750  1.0
  Mo  Mo15  1  0.831  0.669  0.250  1.0
  O  O16  1  0.361  0.639  0.501  1.0
  O  O17  1  0.139  0.861  0.001  1.0
  O  O18  1  0.639  0.361  0.499  1.0
  O  O19  1  0.861  0.139  0.999  1.0
  O  O20  1  0.377  0.623  0.029  1.0
  O  O21  1  0.123  0.877  0.529  1.0
  O  O22  1  0.623  0.377  0.971  1.0
  O  O23  1  0.877  0.123  0.471  1.0
  O  O24  1  0.121  0.879  0.282  1.0
  O  O25  1  0.379  0.621  0.782  1.0
  O  O26  1  0.879  0.121  0.718  1.0
  O  O27  1  0.621  0.379  0.218  1.0
  O  O28  1  0.709  0.690  0.662  1.0
  O  O29  1  0.791  0.810  0.162  1.0
  O  O30  1  0.690  0.709  0.338  1.0
  O  O31  1  0.810  0.791  0.838  1.0
  O  O32  1  0.933  0.470  0.345  1.0
  O  O33  1  0.567  0.030  0.845  1.0
  O  O34  1  0.470  0.933  0.655  1.0
  O  O35  1  0.030  0.567  0.155  1.0
  O  O36  1  0.067  0.530  0.655  1.0
  O  O37  1  0.433  0.970  0.155  1.0
  O  O38  1  0.530  0.067  0.345  1.0
  O  O39  1  0.970  0.433  0.845  1.0
  O  O40  1  0.190  0.209  0.162  1.0
  O  O41  1  0.310  0.291  0.662  1.0
  O  O42  1  0.209  0.190  0.838  1.0
  O  O43  1  0.291  0.310  0.338  1.0
[/CIF]
.