data_Np3As4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.35
_cell_length_b   7.35
_cell_length_c   7.35
_cell_angle_alpha   109.47
_cell_angle_beta   109.47
_cell_angle_gamma   109.47
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Np3As4
_chemical_formula_sum   'Np6 As8'
_cell_volume   305.78
_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
  Np  Np8  1  0.0  0.37  0.06  1.0
  Np  Np9  1  0.06  0.0  0.37  1.0
  Np  Np10  1  0.0  0.12  0.18  1.0
  Np  Np11  1  0.12  0.18  0.0  1.0
  Np  Np12  1  0.18  0.0  0.12  1.0
  Np  Np13  1  0.37  0.06  0.0  1.0
  As  As0  1  0.57  0.68  0.32  1.0
  As  As1  1  0.69  0.55  0.45  1.0
  As  As2  1  0.55  0.45  0.69  1.0
  As  As3  1  0.8  0.8  0.8  1.0
  As  As4  1  0.45  0.69  0.55  1.0
  As  As5  1  0.32  0.57  0.68  1.0
  As  As6  1  0.68  0.32  0.57  1.0
  As  As7  1  0.68  0.68  0.68  1.0

data_Np3As4
_symmetry_space_group_name_H-M   R3
_cell_length_a   12.0
_cell_length_b   12.0
_cell_length_c   7.35
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   146
_chemical_formula_structural   Np3As4
_chemical_formula_sum   'Np18 As24'
_cell_volume   917.33
_cell_formula_units_Z   6
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  'x+2/3, y+1/3, z+1/3'
  5  '-y+2/3, x-y+1/3, z+1/3'
  6  '-x+y+2/3, -x+1/3, z+1/3'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
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
  Np  Np0  9  0.02  0.1  0.1  1.0
  Np  Np1  9  0.19  0.75  0.81  1.0
  As  As2  9  0.05  0.2  0.52  1.0
  As  As3  9  0.13  0.12  0.56  1.0
  As  As4  3  0.0  0.0  0.68  1.0
  As  As5  3  0.0  0.0  0.8  1.0

Np Np Np Np Np Np As As As As As As As As
Np3As4 crystallizes in the trigonal R3 space group. There are two inequivalent Np sites. In the first Np site, Np(1) is bonded in a 5-coordinate geometry to two equivalent Np(2), one As(2), and two equivalent As(1) atoms. There is one shorter (1.87 Å) and one longer (2.26 Å) Np(1)-Np(2) bond length. The Np(1)-As(2) bond length is 3.27 Å. There is one shorter (3.42 Å) and one longer (3.45 Å) Np(1)-As(1) bond length. In the second Np site, Np(2) is bonded in a 6-coordinate geometry to two equivalent Np(1), two equivalent Np(2), one As(1), and one As(3) atom. Both Np(2)-Np(2) bond lengths are 1.94 Å. The Np(2)-As(1) bond length is 3.27 Å. The Np(2)-As(3) bond length is 2.50 Å. There are four inequivalent As sites. In the first As site, As(1) is bonded in a 5-coordinate geometry to one Np(2), two equivalent Np(1), and two equivalent As(2) atoms. There is one shorter (1.72 Å) and one longer (2.15 Å) As(1)-As(2) bond length. In the second As site, As(2) is bonded in a 4-coordinate geometry to one Np(1), one As(4), and two equivalent As(1) atoms. The As(2)-As(4) bond length is 1.68 Å. In the third As site, As(3) is bonded in a distorted single-bond geometry to three equivalent Np(2) and one As(4) atom. The As(3)-As(4) bond length is 0.90 Å. In the fourth As site, As(4) is bonded in a 4-coordinate geometry to one As(3) and three equivalent As(2) atoms.