data_global
_chemical_name_mineral 'Neptunium-alpha'
loop_
_publ_author_name
'Wyckoff R W G'
_journal_name_full 'Crystal Structures'
_journal_volume 1 
_journal_year 1963
_journal_page_first 7
_journal_page_last 83
_publ_section_title
;
 Second edition. Interscience Publishers, New York, New York
 Sample is stable at room conditions
;
_database_code_amcsd 0011263
_chemical_formula_sum 'Np'
_cell_length_a 4.723
_cell_length_b 4.887
_cell_length_c 6.663
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 153.791
_exptl_crystal_density_diffrn     20.472
_symmetry_space_group_name_H-M 'P m c n'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2-x,y,z'
  '1/2+x,-y,-z'
  '1/2+x,1/2+y,1/2-z'
  '1/2-x,1/2-y,1/2+z'
  'x,1/2-y,1/2+z'
  '-x,1/2+y,1/2-z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Np1   0.25000   0.20800   0.03600
Np2   0.25000   0.84200   0.31900