data_global
_chemical_name_mineral 'Ice II'
loop_
_publ_author_name
'Kamb B'
_journal_name_full 'Acta Crystallographica'
_journal_volume 17 
_journal_year 1964
_journal_page_first 1437
_journal_page_last 1449
_publ_section_title
;
 Ice II: A proton-ordered form of ice
 Note: T = -75 C, P = 0.3 GPa
;
_database_code_amcsd 0018367
_chemical_compound_source 'Synthetic'
_chemical_formula_sum 'O H2'
_cell_length_a 7.78
_cell_length_b 7.78
_cell_length_c 7.78
_cell_angle_alpha 113.1
_cell_angle_beta 113.1
_cell_angle_gamma 113.1
_cell_volume 304.251
_exptl_crystal_density_diffrn      1.180
_symmetry_space_group_name_H-M 'R -3'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '-z,-x,-y'
  'y,z,x'
  '-x,-y,-z'
  'z,x,y'
  '-y,-z,-x'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
O1   0.27300   0.02400  -0.14600   0.02444
O2   0.47800   0.75000   0.33200   0.02254
H1   0.16500   0.06900  -0.19000   0.02660
H2   0.41300   0.20500  -0.00300   0.02660
H3   0.71900   0.40100   0.39500   0.02660
H4   0.74100   0.20300   0.36000   0.02660