data_global _chemical_name_mineral 'Willemite' loop_ _publ_author_name 'Simonov M A' 'Sandomirskii P A' 'Egorov-Tismenko Y K' 'Belov N V' _journal_name_full 'Doklady Akademii Nauk SSSR' _journal_volume 237 _journal_year 1977 _journal_page_first 581 _journal_page_last 584 _publ_section_title ; The crystal structure of willemite Zn2[SiO4] ; _database_code_amcsd 0018743 _chemical_compound_source 'Franklin, New Jersey, USA' _chemical_formula_sum 'Zn2 Si O4' _cell_length_a 13.971 _cell_length_b 13.971 _cell_length_c 9.334 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 1577.805 _exptl_crystal_density_diffrn 4.222 _symmetry_space_group_name_H-M 'R -3' loop_ _space_group_symop_operation_xyz 'x,y,z' '2/3+x,1/3+y,1/3+z' '1/3+x,2/3+y,2/3+z' 'y,-x+y,-z' '2/3+y,1/3-x+y,1/3-z' '1/3+y,2/3-x+y,2/3-z' '-x+y,-x,z' '2/3-x+y,1/3-x,1/3+z' '1/3-x+y,2/3-x,2/3+z' '-x,-y,-z' '2/3-x,1/3-y,1/3-z' '1/3-x,2/3-y,2/3-z' '-y,x-y,z' '2/3-y,1/3+x-y,1/3+z' '1/3-y,2/3+x-y,2/3+z' 'x-y,x,-z' '2/3+x-y,1/3+x,1/3-z' '1/3+x-y,2/3+x,2/3-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv Zn1 0.19160 0.20870 0.58440 0.00836 Zn2 0.19210 0.21550 0.91850 0.00912 Si 0.19630 0.21180 0.25100 0.00899 O1 0.12670 0.20850 0.10820 0.01077 O2 0.12950 0.20590 0.39550 0.00975 O3 0.11000 0.21750 0.74960 0.01013 O4 0.31650 0.32150 0.24930 0.01254