data_global _chemical_name_mineral 'Phenakite' loop_ _publ_author_name 'Hazen R M' 'Finger L W' _journal_name_full 'Physics and Chemistry of Minerals' _journal_volume 14 _journal_year 1987 _journal_page_first 426 _journal_page_last 434 _publ_section_title ; High-temperature crystal chemistry of phenakite (Be2SiO4) and Chrysoberyl (BeAl2O4) Sample: T = 270 C ; _database_code_amcsd 0007440 _chemical_formula_sum 'Be2 Si O4' _cell_length_a 12.449 _cell_length_b 12.449 _cell_length_c 8.240 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 1105.928 _exptl_crystal_density_diffrn 2.976 _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 0.19384 0.20985 0.41545 0.00811 Be2 0.19430 0.21157 0.08379 0.00849 Si 0.19557 0.21152 0.74995 0.00469 O1 0.20965 0.08856 0.75032 0.00747 O2 0.33348 0.33323 0.75008 0.00671 O3 0.12234 0.20978 0.91468 0.00760 O4 0.12233 0.20884 0.58555 0.00722