data_global _chemical_name_mineral 'Quartz' loop_ _publ_author_name 'Levien L' 'Prewitt C T' 'Weidner D J' _journal_name_full 'American Mineralogist' _journal_volume 65 _journal_year 1980 _journal_page_first 920 _journal_page_last 930 _publ_section_title ; Structure and elastic properties of quartz at pressure P = 55.8 kbar ; _database_code_amcsd 0000793 _chemical_formula_sum 'Si O2' _cell_length_a 4.722 _cell_length_b 4.722 _cell_length_c 5.267 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 101.706 _exptl_crystal_density_diffrn 2.943 _symmetry_space_group_name_H-M 'P 32 2 1' loop_ _space_group_symop_operation_xyz 'x,y,z' 'y,x,2/3-z' '-y,x-y,2/3+z' '-x,-x+y,1/3-z' '-x+y,-x,1/3+z' 'x-y,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z Si 0.45370 0.00000 0.00000 O 0.40470 0.29260 0.09980 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 Si 0.00695 0.00627 0.00506 0.00313 -0.00022 -0.00044 O 0.01296 0.00991 0.00871 0.00669 -0.00349 -0.00327