data_global _chemical_name_mineral 'Forsterite' loop_ _publ_author_name 'Hazen R M' _journal_name_full 'American Mineralogist' _journal_volume 61 _journal_year 1976 _journal_page_first 1280 _journal_page_last 1293 _publ_section_title ; Effects of temperature and pressure on the crystal structure of forsterite T = 23 C P = 50 kb olivine ; _database_code_amcsd 0000552 _chemical_formula_sum 'Si Mg2 O4' _cell_length_a 4.712 _cell_length_b 9.97 _cell_length_c 5.955 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 279.758 _exptl_crystal_density_diffrn 3.340 _symmetry_space_group_name_H-M 'P b n m' loop_ _space_group_symop_operation_xyz 'x,y,z' 'x,y,1/2-z' '-x,-y,1/2+z' '1/2+x,1/2-y,1/2+z' '1/2-x,1/2+y,1/2-z' '1/2-x,1/2+y,z' '1/2+x,1/2-y,-z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv Si 0.42800 0.10100 0.25000 0.00887 Mg1 0.00000 0.00000 0.00000 0.00253 Mg2 0.99300 0.28300 0.25000 0.00760 O1 0.77600 0.10300 0.25000 0.00127 O2 0.22800 0.44000 0.25000 0.00507 O3 0.28100 0.15300 0.03200 0.00760