The structure described by NaAs3H2O9 crystallizes in the triclinic P-1 space group. Na(1) is bonded to one O(2), one O(3), one O(5), one O(7), and two equivalent O(1) atoms to form distorted NaO6 octahedra that share corners with two equivalent As(2)O6 octahedra, corners with two equivalent As(3)O4 tetrahedra, corners with three equivalent As(1)O4 tetrahedra, and  an edgeedge with one Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-56°. There are three inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(2), one O(4), and one O(6) atom to form AsO4 tetrahedra that share corners with two equivalent As(2)O6 octahedra and corners with three equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-60°. In the second As site, As(2) is bonded to one O(4), one O(6), one O(8), one O(9), and two equivalent O(5) atoms to form AsO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(3)O4 tetrahedra, and  an edgeedge with one As(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-56°. In the third As site, As(3) is bonded to one O(3), one O(7), one O(8), and one O(9) atom to form AsO4 tetrahedra that share corners with two equivalent Na(1)O6 octahedra and corners with two equivalent As(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-63°. There are two inequivalent H sites. In the first H site, H(1) is bonded in a linear geometry to one O(2) and one O(3) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(7) atom. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Na(1) and one As(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one As(1), and one H(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Na(1), one As(3), and one H(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one As(1) and one As(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Na(1) and two equivalent As(2) atoms. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one As(1) and one As(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(1), one As(3), and one H(2) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one As(2) and one As(3) atom. In the ninth O site, O(9) is bonded in a bent 120 degrees geometry to one As(2) and one As(3) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_NaAs3H2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.339
_cell_length_b   7.717
_cell_length_c   8.039
_cell_angle_alpha   110.527
_cell_angle_beta   107.505
_cell_angle_gamma   106.202
_symmetry_Int_Tables_number   1
_cell_volume   366.985
_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  0.686  0.178  0.959  1.0
  Na  Na1  1  0.314  0.822  0.041  1.0
  As  As2  1  0.636  0.655  0.833  1.0
  As  As3  1  0.364  0.345  0.167  1.0
  As  As4  1  0.847  0.567  0.523  1.0
  As  As5  1  0.153  0.433  0.477  1.0
  As  As6  1  0.810  0.164  0.545  1.0
  As  As7  1  0.190  0.836  0.455  1.0
  H  H8  1  0.878  0.641  0.078  1.0
  H  H9  1  0.122  0.359  0.922  1.0
  H  H10  1  0.630  0.807  0.375  1.0
  H  H11  1  0.370  0.193  0.625  1.0
  O  O12  1  0.608  0.861  0.955  1.0
  O  O13  1  0.392  0.139  0.045  1.0
  O  O14  1  0.727  0.537  0.968  1.0
  O  O15  1  0.273  0.463  0.032  1.0
  O  O16  1  0.893  0.195  0.775  1.0
  O  O17  1  0.107  0.805  0.225  1.0
  O  O18  1  0.819  0.723  0.740  1.0
  O  O19  1  0.181  0.277  0.260  1.0
  O  O20  1  0.908  0.431  0.318  1.0
  O  O21  1  0.092  0.569  0.682  1.0
  O  O22  1  0.604  0.560  0.352  1.0
  O  O23  1  0.396  0.440  0.648  1.0
  O  O24  1  0.602  0.923  0.365  1.0
  O  O25  1  0.398  0.077  0.635  1.0
  O  O26  1  0.993  0.819  0.540  1.0
  O  O27  1  0.007  0.181  0.460  1.0
  O  O28  1  0.682  0.316  0.499  1.0
  O  O29  1  0.318  0.684  0.501  1.0
[/CIF]
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The structure described by NaAs3H2O9 crystallizes in the triclinic P-1 space group. Na(1) is bonded to one O(2), one O(3), one O(5), one O(7), and two equivalent O(1) atoms to form distorted NaO6 octahedra that share corners with two equivalent As(2)O6 octahedra, corners with two equivalent As(3)O4 tetrahedra, corners with three equivalent As(1)O4 tetrahedra, and  an edgeedge with one Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-56°. There are three inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(2), one O(4), and one O(6) atom to form AsO4 tetrahedra that share corners with two equivalent As(2)O6 octahedra and corners with three equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-60°. In the second As site, As(2) is bonded to one O(4), one O(6), one O(8), one O(9), and two equivalent O(5) atoms to form AsO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(3)O4 tetrahedra, and  an edgeedge with one As(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-56°. In the third As site, As(3) is bonded to one O(3), one O(7), one O(8), and one O(9) atom to form AsO4 tetrahedra that share corners with two equivalent Na(1)O6 octahedra and corners with two equivalent As(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-63°. There are two inequivalent H sites. In the first H site, H(1) is bonded in a linear geometry to one O(2) and one O(3) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(7) atom. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Na(1) and one As(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one As(1), and one H(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Na(1), one As(3), and one H(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one As(1) and one As(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Na(1) and two equivalent As(2) atoms. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one As(1) and one As(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(1), one As(3), and one H(2) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one As(2) and one As(3) atom. In the ninth O site, O(9) is bonded in a bent 120 degrees geometry to one As(2) and one As(3) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_NaAs3H2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.339
_cell_length_b   7.717
_cell_length_c   8.039
_cell_angle_alpha   110.527
_cell_angle_beta   107.505
_cell_angle_gamma   106.202
_symmetry_Int_Tables_number   1
_cell_volume   366.985
_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  0.686  0.178  0.959  1.0
  Na  Na1  1  0.314  0.822  0.041  1.0
  As  As2  1  0.636  0.655  0.833  1.0
  As  As3  1  0.364  0.345  0.167  1.0
  As  As4  1  0.847  0.567  0.523  1.0
  As  As5  1  0.153  0.433  0.477  1.0
  As  As6  1  0.810  0.164  0.545  1.0
  As  As7  1  0.190  0.836  0.455  1.0
  H  H8  1  0.878  0.641  0.078  1.0
  H  H9  1  0.122  0.359  0.922  1.0
  H  H10  1  0.630  0.807  0.375  1.0
  H  H11  1  0.370  0.193  0.625  1.0
  O  O12  1  0.608  0.861  0.955  1.0
  O  O13  1  0.392  0.139  0.045  1.0
  O  O14  1  0.727  0.537  0.968  1.0
  O  O15  1  0.273  0.463  0.032  1.0
  O  O16  1  0.893  0.195  0.775  1.0
  O  O17  1  0.107  0.805  0.225  1.0
  O  O18  1  0.819  0.723  0.740  1.0
  O  O19  1  0.181  0.277  0.260  1.0
  O  O20  1  0.908  0.431  0.318  1.0
  O  O21  1  0.092  0.569  0.682  1.0
  O  O22  1  0.604  0.560  0.352  1.0
  O  O23  1  0.396  0.440  0.648  1.0
  O  O24  1  0.602  0.923  0.365  1.0
  O  O25  1  0.398  0.077  0.635  1.0
  O  O26  1  0.993  0.819  0.540  1.0
  O  O27  1  0.007  0.181  0.460  1.0
  O  O28  1  0.682  0.316  0.499  1.0
  O  O29  1  0.318  0.684  0.501  1.0
[/CIF]
.