data_global
_chemical_name_mineral 'Urea'
loop_
_publ_author_name
'Swaminathan S'
'Craven B M'
_journal_name_full 'Acta Crystallographica, Section B'
_journal_volume 40 
_journal_year 1984
_journal_page_first 300
_journal_page_last 306
_publ_section_title
;
 The crystal structure and molecular thermal motion of urea
 at 12, 60 and 123 K from neutron diffraction
 Note: neutron data, T = 123 K
;
_database_code_amcsd 0020672
_chemical_compound_source 'Synthetic'
_chemical_formula_sum 'C H4 N2 O'
_cell_length_a 5.584
_cell_length_b 5.584
_cell_length_c 4.689
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 146.208
_exptl_crystal_density_diffrn      1.364
_symmetry_space_group_name_H-M 'P -4 21 m'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2-y,1/2-x,z'
  'y,-x,-z'
  '1/2-x,1/2+y,-z'
  '-x,-y,z'
  '1/2+y,1/2+x,z'
  '-y,x,-z'
  '1/2+x,1/2-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
C   0.00000   0.50000   0.32800
H1   0.25570   0.75570   0.28410
H2   0.14310   0.64310  -0.03480
N   0.14470   0.64470   0.17850
O   0.00000   0.50000   0.59620
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
C 0.01470 0.01470 0.00650 0.00010 0.00000 0.00000
H1 0.04400 0.04400 0.02160 -0.02220 -0.00310 -0.00310
H2 0.04300 0.04300 0.01400 -0.01580 0.00190 0.00190
N 0.02860 0.02860 0.00950 -0.01470 0.00020 0.00020
O 0.01970 0.01970 0.00630 0.00170 0.00000 0.00000