data_Na2MnAs
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.35
_cell_length_b   10.35
_cell_length_c   10.35
_cell_angle_alpha   15.91
_cell_angle_beta   15.91
_cell_angle_gamma   15.91
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2MnAs
_chemical_formula_sum   'Na2 Mn1 As1'
_cell_volume   72.54
_cell_formula_units_Z   1
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  Na2  1  0.0  0.0  0.67  1.0
  Na  Na3  1  0.0  0.0  0.97  1.0
  Mn  Mn1  1  0.0  0.0  0.0  1.0
  As  As0  1  0.0  0.0  0.32  1.0

data_Na2MnAs
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.96
_cell_length_b   2.86
_cell_length_c   10.35
_cell_angle_alpha   90.0
_cell_angle_beta   99.19
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Na2MnAs
_chemical_formula_sum   'Na4 Mn2 As2'
_cell_volume   145.08
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  2  0.0  0.0  0.03  1.0
  Na  Na1  2  0.0  0.0  0.33  1.0
  Mn  Mn2  2  0.0  0.0  0.0  1.0
  As  As3  2  0.0  0.0  0.68  1.0

Na Na Mn As
Na Na Mn As 0 0 o + - 0 0 + - o 0 0 + o - 0 2 o o + 0 1 o o o 1 2 o o + 2 3 o o o 3 3 o + - 3 3 + - o 3 3 + o - 
Na2MnAs crystallizes in the monoclinic Cm space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one Na(2), six equivalent Na(1), and one As(1) atom to form distorted NaNa7As hexagonal bipyramids that share corners with six equivalent Na(1)Na7As hexagonal bipyramids, edges with six equivalent As(1)NaMnAs6 hexagonal bipyramids, and edges with twelve equivalent Na(1)Na7As hexagonal bipyramids. The Na(1)-Na(2) bond length is 3.10 Å. All Na(1)-Na(1) bond lengths are 2.86 Å. The Na(1)-As(1) bond length is 3.62 Å. In the second Na site, Na(2) is bonded in a single-bond geometry to one Na(1) and one Mn(1) atom. The Na(2)-Mn(1) bond length is 0.28 Å. Mn(1) is bonded in a single-bond geometry to one Na(2) and one As(1) atom. The Mn(1)-As(1) bond length is 3.34 Å. As(1) is bonded to one Na(1), one Mn(1), and six equivalent As(1) atoms to form distorted AsNaMnAs6 hexagonal bipyramids that share corners with six equivalent As(1)NaMnAs6 hexagonal bipyramids, edges with six equivalent Na(1)Na7As hexagonal bipyramids, and edges with twelve equivalent As(1)NaMnAs6 hexagonal bipyramids. All As(1)-As(1) bond lengths are 2.86 Å.