The material structure described by NpSi2 is hexagonal omega structure-like structured and crystallizes in the tetragonal I4_1/amd space group. Np(1) is bonded to twelve equivalent Si(1) atoms to form a mixture of face and edge-sharing NpSi12 cuboctahedra. Si(1) is bonded in a 9-coordinate geometry to six equivalent Np(1) and three equivalent Si(1) atoms. is represented by the CIF card [CIF]
data_NpSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.955
_cell_length_b   3.955
_cell_length_c   7.658
_cell_angle_alpha   104.967
_cell_angle_beta   104.967
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   111.536
_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  Np0  1  0.875  0.625  0.250  1.0
  Np  Np1  1  0.125  0.375  0.750  1.0
  Si  Si2  1  0.707  0.957  0.914  1.0
  Si  Si3  1  0.457  0.207  0.414  1.0
  Si  Si4  1  0.543  0.793  0.586  1.0
  Si  Si5  1  0.293  0.043  0.086  1.0
[/CIF]
.
The material structure described by NpSi2 is hexagonal omega structure-like structured and crystallizes in the tetragonal I4_1/amd space group. Np(1) is bonded to twelve equivalent Si(1) atoms to form a mixture of face and edge-sharing NpSi12 cuboctahedra. Si(1) is bonded in a 9-coordinate geometry to six equivalent Np(1) and three equivalent Si(1) atoms. is represented by the CIF card [CIF]
data_NpSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.955
_cell_length_b   3.955
_cell_length_c   7.658
_cell_angle_alpha   104.967
_cell_angle_beta   104.967
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   111.536
_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  Np0  1  0.875  0.625  0.250  1.0
  Np  Np1  1  0.125  0.375  0.750  1.0
  Si  Si2  1  0.707  0.957  0.914  1.0
  Si  Si3  1  0.457  0.207  0.414  1.0
  Si  Si4  1  0.543  0.793  0.586  1.0
  Si  Si5  1  0.293  0.043  0.086  1.0
[/CIF]
.