data_NpTa
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.88
_cell_length_b   2.88
_cell_length_c   5.56
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NpTa
_chemical_formula_sum   'Np1 Ta1'
_cell_volume   40.02
_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
  Np  Np0  1  0.0  0.66  0.78  1.0
  Ta  Ta1  1  0.0  0.0  0.0  1.0

data_NpTa
_symmetry_space_group_name_H-M   Cm
_cell_length_a   2.88
_cell_length_b   4.99
_cell_length_c   5.56
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   NpTa
_chemical_formula_sum   'Np2 Ta2'
_cell_volume   80.04
_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
  Np  Np0  2  0.16  0.5  0.78  1.0
  Ta  Ta1  2  0.5  0.5  0.0  1.0

Np Ta
NpTa crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two NpTa clusters. Np(1) is bonded in a distorted single-bond geometry to one Ta(1) atom. The Np(1)-Ta(1) bond length is 1.56 Å. Ta(1) is bonded in a distorted single-bond geometry to one Np(1) atom.