data_global _chemical_name_mineral 'Hemimorphite' loop_ _publ_author_name 'Libowitzky E' 'Kohler T' 'Armbruster T' 'Rossman G R' _journal_name_full 'European Journal of Mineralogy' _journal_volume 9 _journal_year 1997 _journal_page_first 803 _journal_page_last 810 _publ_section_title ; Proton disorder in dehydrated hemimorphite - IR spectroscopy and X-ray structure refinement at low and ambient temperatures T = 110 K ; _database_code_amcsd 0006696 _chemical_formula_sum 'Zn4 Si2 O9 H2' _cell_length_a 8.181 _cell_length_b 10.841 _cell_length_c 5.081 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 450.635 _exptl_crystal_density_diffrn 3.418 _symmetry_space_group_name_H-M 'I m m 2' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2+y,1/2+z' 'x,-y,z' '1/2+x,1/2-y,1/2+z' '-x,y,z' '1/2-x,1/2+y,1/2+z' '-x,-y,z' '1/2-x,1/2-y,1/2+z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy _atom_site_U_iso_or_equiv Zn 0.78969 0.84232 0.00000 1.00000 0.00475 Si 0.00000 0.85672 0.49080 1.00000 0.00384 O1 0.83620 0.79640 0.36490 1.00000 0.00600 O2 0.00000 0.84160 0.80840 1.00000 0.00600 O3 0.68260 0.00000 0.94530 1.00000 0.01290 O4 0.00000 0.00000 0.39670 1.00000 0.00660 H3 0.69000 0.00000 0.75900 0.50000 0.05000 H3* 0.56900 0.00000 0.98000 0.50000 0.05000 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 Zn 0.00602 0.00367 0.00458 -0.00075 -0.00007 0.00008 Si 0.00520 0.00260 0.00370 0.00000 0.00000 -0.00030 O1 0.00860 0.00650 0.00520 -0.00360 -0.00080 0.00080 O2 0.00670 0.00660 0.00490 0.00000 0.00000 0.00040 O3 0.00750 0.00440 0.02670 0.00000 -0.00070 0.00000 O4 0.01020 0.00260 0.00710 0.00000 0.00000 0.00000