data_global _chemical_name_mineral 'Quartz' loop_ _publ_author_name 'Kihara K' _journal_name_full 'European Journal of Mineralogy' _journal_volume 2 _journal_year 1990 _journal_page_first 63 _journal_page_last 77 _publ_section_title ; An X-ray study of the temperature dependence of the quartz structure Sample: at T = 972 K ; _database_code_amcsd 0006376 _chemical_formula_sum 'Si O2' _cell_length_a 4.9977 _cell_length_b 4.9977 _cell_length_c 5.4564 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 118.026 _exptl_crystal_density_diffrn 2.536 _symmetry_space_group_name_H-M 'P 62 2 2' loop_ _space_group_symop_operation_xyz 'x,y,z' 'x,x-y,1/3-z' 'x-y,x,1/3+z' 'y,x,2/3-z' '-y,x-y,2/3+z' '-x+y,y,-z' '-x,-y,z' '-x,-x+y,1/3-z' '-x+y,-x,1/3+z' '-y,-x,2/3-z' 'y,-x+y,2/3+z' 'x-y,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z Si 0.50000 0.00000 0.00000 O 0.41590 0.20795 0.16667 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 0.02638 0.02069 0.02081 0.01034 0.00000 0.00000 O 0.05514 0.05419 0.05943 0.02757 0.00000 -0.03039