data_global _chemical_name_mineral 'Ice' loop_ _publ_author_name 'Fortes A D' 'Wood I G' 'Grigoriev D' 'Alfredsson M' 'Kipfstuhl S' 'Knight K S' 'Smith R I' _journal_name_full 'Journal of Chemical Physics' _journal_volume 120 _journal_year 2004 _journal_page_first 11376 _journal_page_last 11379 _publ_section_title ; No evidence for large-scale proton ordering in Antarctic ice from powder neutron diffraction Note: T = 100 K Note: known as ice-IH ; _database_code_amcsd 0018366 _chemical_compound_source 'Kohen Station, Antarctica' _chemical_formula_sum 'O H2' _cell_length_a 4.497479 _cell_length_b 4.497479 _cell_length_c 7.322382 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 128.269 _exptl_crystal_density_diffrn 0.933 _symmetry_space_group_name_H-M 'P 63/m m c' loop_ _space_group_symop_operation_xyz 'x,y,z' '-x,-x+y,1/2+z' 'x,x-y,1/2-z' '-x+y,-x,1/2-z' 'x-y,x,1/2+z' '-y,-x,z' 'y,x,-z' 'y,-x+y,-z' '-y,x-y,z' 'x-y,-y,1/2+z' '-x+y,y,1/2-z' 'x,y,1/2-z' '-x,-y,1/2+z' 'x,x-y,z' '-x,-x+y,-z' 'x-y,x,-z' '-x+y,-x,z' 'y,x,1/2+z' '-y,-x,1/2-z' '-y,x-y,1/2-z' 'y,-x+y,1/2+z' '-x+y,y,z' 'x-y,-y,-z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy O 0.33333 0.66667 0.06140 1.00000 H1 0.33333 0.66667 0.19640 0.50000 H2 0.45100 0.90190 0.01790 0.50000 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 O 0.00790 0.00790 0.00600 0.00400 0.00000 0.00000 H1 0.02110 0.02110 0.00820 0.01060 0.00000 0.00000 H2 0.01690 0.01240 0.01740 0.00620 0.00370 0.00750