data_global _chemical_name_mineral 'Willemite' loop_ _publ_author_name 'Hang C' 'Simonov M A' 'Belov N V' _journal_name_full 'Soviet Physics Crystallography' _journal_volume 15 _journal_year 1970 _journal_page_first 387 _journal_page_last 390 _publ_section_title ; Crystal structures of willemite Zn2[SiO4] and its germanium analog Zn2[GeO4] ; _database_code_amcsd 0018744 _chemical_compound_source 'Synthetic' _chemical_formula_sum 'Zn2 Si O4' _cell_length_a 8.628 _cell_length_b 8.628 _cell_length_c 8.628 _cell_angle_alpha 107.87 _cell_angle_beta 107.87 _cell_angle_gamma 107.87 _cell_volume 521.689 _exptl_crystal_density_diffrn 4.256 _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 Zn1 0.79300 0.56200 0.38500 Zn2 0.12800 0.89700 0.72000 Si 0.45900 0.22500 0.05100 O1 0.32900 0.01900 -0.02700 O2 0.61400 0.30700 0.25800 O3 0.97100 0.63900 0.64000 O4 0.55300 0.22900 -0.09200