The material described by Na2MnH4(SeO5)2 crystallizes in the monoclinic P2_1/c space group. Na(1) is bonded to one O(1), one O(3), one O(5), two equivalent O(2), and two equivalent O(4) atoms to form distorted NaO7 pentagonal bipyramids that share corners with two equivalent Na(1)O7 pentagonal bipyramids, corners with four equivalent Se(1)O4 tetrahedra, edges with two equivalent Mn(1)O6 octahedra,  an edgeedge with one Na(1)O7 pentagonal bipyramid, and  an edgeedge with one Se(1)O4 tetrahedra. Mn(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form MnO6 octahedra that share corners with four equivalent Se(1)O4 tetrahedra and edges with four equivalent Na(1)O7 pentagonal bipyramids. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(1) and one O(5) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(4) and one O(5) atom. Se(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SeO4 tetrahedra that share corners with two equivalent Mn(1)O6 octahedra, corners with four equivalent Na(1)O7 pentagonal bipyramids, and  an edgeedge with one Na(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 44-52°. There are five inequivalent O sites. In the first O site, O(5) is bonded in a distorted water-like geometry to one Na(1), one Mn(1), one H(1), and one H(2) atom. In the second O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one H(1), and one Se(1) atom. In the third O site, O(2) is bonded to two equivalent Na(1), one Mn(1), and one Se(1) atom to form a mixture of distorted edge and corner-sharing ONa2MnSe tetrahedra. In the fourth O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Na(1), one Mn(1), and one Se(1) atom. In the fifth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Na(1), one H(2), and one Se(1) atom. is represented by the CIF file [CIF]
data_Na2MnH4(SeO5)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.791
_cell_length_b   6.027
_cell_length_c   13.705
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   105.830
_symmetry_Int_Tables_number   1
_cell_volume   460.164
_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
  Na  Na0  1  0.738  0.573  0.377  1.0
  Na  Na1  1  0.762  0.427  0.877  1.0
  Na  Na2  1  0.262  0.427  0.623  1.0
  Na  Na3  1  0.238  0.573  0.123  1.0
  Mn  Mn4  1  0.500  0.000  0.500  1.0
  Mn  Mn5  1  0.000  0.000  0.000  1.0
  H  H6  1  0.496  0.906  0.301  1.0
  H  H7  1  0.004  0.094  0.801  1.0
  H  H8  1  0.504  0.094  0.699  1.0
  H  H9  1  0.996  0.906  0.199  1.0
  H  H10  1  0.310  0.695  0.351  1.0
  H  H11  1  0.190  0.305  0.851  1.0
  H  H12  1  0.690  0.305  0.649  1.0
  H  H13  1  0.810  0.695  0.149  1.0
  Se  Se14  1  0.067  0.224  0.382  1.0
  Se  Se15  1  0.433  0.776  0.882  1.0
  Se  Se16  1  0.933  0.776  0.618  1.0
  Se  Se17  1  0.567  0.224  0.118  1.0
  O  O18  1  0.004  0.973  0.323  1.0
  O  O19  1  0.496  0.027  0.823  1.0
  O  O20  1  0.996  0.027  0.677  1.0
  O  O21  1  0.504  0.973  0.177  1.0
  O  O22  1  0.323  0.267  0.447  1.0
  O  O23  1  0.177  0.733  0.947  1.0
  O  O24  1  0.677  0.733  0.553  1.0
  O  O25  1  0.823  0.267  0.053  1.0
  O  O26  1  0.842  0.234  0.459  1.0
  O  O27  1  0.658  0.766  0.959  1.0
  O  O28  1  0.158  0.766  0.541  1.0
  O  O29  1  0.342  0.234  0.041  1.0
  O  O30  1  0.091  0.449  0.307  1.0
  O  O31  1  0.409  0.551  0.807  1.0
  O  O32  1  0.909  0.551  0.693  1.0
  O  O33  1  0.591  0.449  0.193  1.0
  O  O34  1  0.466  0.813  0.362  1.0
  O  O35  1  0.034  0.187  0.862  1.0
  O  O36  1  0.534  0.187  0.638  1.0
  O  O37  1  0.966  0.813  0.138  1.0
[/CIF]
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The material described by Na2MnH4(SeO5)2 crystallizes in the monoclinic P2_1/c space group. Na(1) is bonded to one O(1), one O(3), one O(5), two equivalent O(2), and two equivalent O(4) atoms to form distorted NaO7 pentagonal bipyramids that share corners with two equivalent Na(1)O7 pentagonal bipyramids, corners with four equivalent Se(1)O4 tetrahedra, edges with two equivalent Mn(1)O6 octahedra,  an edgeedge with one Na(1)O7 pentagonal bipyramid, and  an edgeedge with one Se(1)O4 tetrahedra. Mn(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form MnO6 octahedra that share corners with four equivalent Se(1)O4 tetrahedra and edges with four equivalent Na(1)O7 pentagonal bipyramids. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(1) and one O(5) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(4) and one O(5) atom. Se(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SeO4 tetrahedra that share corners with two equivalent Mn(1)O6 octahedra, corners with four equivalent Na(1)O7 pentagonal bipyramids, and  an edgeedge with one Na(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 44-52°. There are five inequivalent O sites. In the first O site, O(5) is bonded in a distorted water-like geometry to one Na(1), one Mn(1), one H(1), and one H(2) atom. In the second O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one H(1), and one Se(1) atom. In the third O site, O(2) is bonded to two equivalent Na(1), one Mn(1), and one Se(1) atom to form a mixture of distorted edge and corner-sharing ONa2MnSe tetrahedra. In the fourth O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Na(1), one Mn(1), and one Se(1) atom. In the fifth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Na(1), one H(2), and one Se(1) atom. is represented by the CIF file [CIF]
data_Na2MnH4(SeO5)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.791
_cell_length_b   6.027
_cell_length_c   13.705
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   105.830
_symmetry_Int_Tables_number   1
_cell_volume   460.164
_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
  Na  Na0  1  0.738  0.573  0.377  1.0
  Na  Na1  1  0.762  0.427  0.877  1.0
  Na  Na2  1  0.262  0.427  0.623  1.0
  Na  Na3  1  0.238  0.573  0.123  1.0
  Mn  Mn4  1  0.500  0.000  0.500  1.0
  Mn  Mn5  1  0.000  0.000  0.000  1.0
  H  H6  1  0.496  0.906  0.301  1.0
  H  H7  1  0.004  0.094  0.801  1.0
  H  H8  1  0.504  0.094  0.699  1.0
  H  H9  1  0.996  0.906  0.199  1.0
  H  H10  1  0.310  0.695  0.351  1.0
  H  H11  1  0.190  0.305  0.851  1.0
  H  H12  1  0.690  0.305  0.649  1.0
  H  H13  1  0.810  0.695  0.149  1.0
  Se  Se14  1  0.067  0.224  0.382  1.0
  Se  Se15  1  0.433  0.776  0.882  1.0
  Se  Se16  1  0.933  0.776  0.618  1.0
  Se  Se17  1  0.567  0.224  0.118  1.0
  O  O18  1  0.004  0.973  0.323  1.0
  O  O19  1  0.496  0.027  0.823  1.0
  O  O20  1  0.996  0.027  0.677  1.0
  O  O21  1  0.504  0.973  0.177  1.0
  O  O22  1  0.323  0.267  0.447  1.0
  O  O23  1  0.177  0.733  0.947  1.0
  O  O24  1  0.677  0.733  0.553  1.0
  O  O25  1  0.823  0.267  0.053  1.0
  O  O26  1  0.842  0.234  0.459  1.0
  O  O27  1  0.658  0.766  0.959  1.0
  O  O28  1  0.158  0.766  0.541  1.0
  O  O29  1  0.342  0.234  0.041  1.0
  O  O30  1  0.091  0.449  0.307  1.0
  O  O31  1  0.409  0.551  0.807  1.0
  O  O32  1  0.909  0.551  0.693  1.0
  O  O33  1  0.591  0.449  0.193  1.0
  O  O34  1  0.466  0.813  0.362  1.0
  O  O35  1  0.034  0.187  0.862  1.0
  O  O36  1  0.534  0.187  0.638  1.0
  O  O37  1  0.966  0.813  0.138  1.0
[/CIF]
.