The crystal structure described by Na3AsO4 is Enargite structured and crystallizes in the orthorhombic Pmn2_1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form NaO4 tetrahedra that share corners with four equivalent As(1)O4 tetrahedra and corners with eight equivalent Na(2)O4 tetrahedra. In the second Na site, Na(2) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form NaO4 tetrahedra that share corners with four equivalent Na(1)O4 tetrahedra, corners with four equivalent Na(2)O4 tetrahedra, and corners with four equivalent As(1)O4 tetrahedra. As(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form AsO4 tetrahedra that share corners with four equivalent Na(1)O4 tetrahedra and corners with eight equivalent Na(2)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), two equivalent Na(2), and one As(1) atom to form distorted corner-sharing ONa3As trigonal pyramids. In the second O site, O(2) is bonded to one Na(1), two equivalent Na(2), and one As(1) atom to form corner-sharing ONa3As tetrahedra. In the third O site, O(3) is bonded to one Na(1), two equivalent Na(2), and one As(1) atom to form distorted corner-sharing ONa3As tetrahedra. is represented by the CIF file [CIF]
data_Na3AsO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.006
_cell_length_b   6.037
_cell_length_c   5.501
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   232.661
_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  0.000  0.153  0.490  1.0
  Na  Na1  1  0.245  0.326  0.992  1.0
  Na  Na2  1  0.255  0.674  0.492  1.0
  Na  Na3  1  0.500  0.847  0.990  1.0
  Na  Na4  1  0.745  0.674  0.492  1.0
  Na  Na5  1  0.755  0.326  0.992  1.0
  As  As6  1  0.000  0.823  0.003  1.0
  As  As7  1  0.500  0.177  0.503  1.0
  O  O8  1  0.000  0.092  0.907  1.0
  O  O9  1  0.000  0.817  0.312  1.0
  O  O10  1  0.300  0.309  0.402  1.0
  O  O11  1  0.200  0.691  0.902  1.0
  O  O12  1  0.500  0.183  0.812  1.0
  O  O13  1  0.500  0.908  0.407  1.0
  O  O14  1  0.800  0.691  0.902  1.0
  O  O15  1  0.700  0.309  0.402  1.0
[/CIF]
.
The crystal structure described by Na3AsO4 is Enargite structured and crystallizes in the orthorhombic Pmn2_1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form NaO4 tetrahedra that share corners with four equivalent As(1)O4 tetrahedra and corners with eight equivalent Na(2)O4 tetrahedra. In the second Na site, Na(2) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form NaO4 tetrahedra that share corners with four equivalent Na(1)O4 tetrahedra, corners with four equivalent Na(2)O4 tetrahedra, and corners with four equivalent As(1)O4 tetrahedra. As(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form AsO4 tetrahedra that share corners with four equivalent Na(1)O4 tetrahedra and corners with eight equivalent Na(2)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), two equivalent Na(2), and one As(1) atom to form distorted corner-sharing ONa3As trigonal pyramids. In the second O site, O(2) is bonded to one Na(1), two equivalent Na(2), and one As(1) atom to form corner-sharing ONa3As tetrahedra. In the third O site, O(3) is bonded to one Na(1), two equivalent Na(2), and one As(1) atom to form distorted corner-sharing ONa3As tetrahedra. is represented by the CIF file [CIF]
data_Na3AsO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.006
_cell_length_b   6.037
_cell_length_c   5.501
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   232.661
_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  0.000  0.153  0.490  1.0
  Na  Na1  1  0.245  0.326  0.992  1.0
  Na  Na2  1  0.255  0.674  0.492  1.0
  Na  Na3  1  0.500  0.847  0.990  1.0
  Na  Na4  1  0.745  0.674  0.492  1.0
  Na  Na5  1  0.755  0.326  0.992  1.0
  As  As6  1  0.000  0.823  0.003  1.0
  As  As7  1  0.500  0.177  0.503  1.0
  O  O8  1  0.000  0.092  0.907  1.0
  O  O9  1  0.000  0.817  0.312  1.0
  O  O10  1  0.300  0.309  0.402  1.0
  O  O11  1  0.200  0.691  0.902  1.0
  O  O12  1  0.500  0.183  0.812  1.0
  O  O13  1  0.500  0.908  0.407  1.0
  O  O14  1  0.800  0.691  0.902  1.0
  O  O15  1  0.700  0.309  0.402  1.0
[/CIF]
.