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 = 1 atm olivine ; _database_code_amcsd 0000546 _chemical_formula_sum 'Si Mg2 O4' _cell_length_a 4.752 _cell_length_b 10.193 _cell_length_c 5.977 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 289.509 _exptl_crystal_density_diffrn 3.228 _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 Si 0.42620 0.09400 0.25000 Mg1 0.00000 0.00000 0.00000 Mg2 0.99150 0.27740 0.25000 O1 0.76570 0.09130 0.25000 O2 0.22150 0.44740 0.25000 O3 0.27770 0.16280 0.03310 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 0.00092 0.00226 0.00145 0.00012 0.00000 0.00000 Mg1 0.00275 0.00537 0.00181 0.00025 -0.00043 -0.00093 Mg2 0.00252 0.00316 0.00290 0.00000 0.00000 0.00000 O1 0.00103 0.00474 0.00416 0.00049 0.00000 0.00000 O2 0.00275 0.00368 0.00398 0.00025 0.00000 0.00000 O3 0.00252 0.00490 0.00290 0.00025 -0.00043 0.00123