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