data_global _chemical_name_mineral 'Phenakite' loop_ _publ_author_name 'Hazen R M' 'Au A Y' _journal_name_full 'Physics and Chemistry of Minerals' _journal_volume 13 _journal_year 1986 _journal_page_first 69 _journal_page_last 78 _publ_section_title ; High-pressure crystal chemistry of phenakite (Be2SiO4) and bertrandite (Be4Si2O7(OH)2) Sample: P = 49.5 kbar ; _database_code_amcsd 0007374 _chemical_formula_sum 'Be2 Si O4' _cell_length_a 12.370 _cell_length_b 12.370 _cell_length_c 8.188 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 1085.045 _exptl_crystal_density_diffrn 3.033 _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 Be1 0.19240 0.20960 0.41560 0.01102 Be2 0.19320 0.21210 0.08420 0.01191 Si 0.19500 0.21180 0.74960 0.00621 O1 0.20950 0.08880 0.75080 0.00887 O2 0.33340 0.33360 0.75000 0.01001 O3 0.12190 0.20980 0.91510 0.00874 O4 0.12240 0.20940 0.58400 0.00861