data_global _amcsd_formula_title 'Mg2SiO4' loop_ _publ_author_name 'Baur W H' _journal_name_full 'American Mineralogist' _journal_volume 57 _journal_year 1972 _journal_page_first 709 _journal_page_last 731 _publ_section_title ; Computer-simulated crystal structures of observed and hypothetical Mg2SiO4 polymorphs of low and high density Sr2PbO4 structure ; _database_code_amcsd 0000283 _chemical_compound_source 'hypothetical' _chemical_formula_sum 'Si Mg2 O4' _cell_length_a 4.98 _cell_length_b 8.85 _cell_length_c 2.75 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 121.201 _exptl_crystal_density_diffrn 3.855 _symmetry_space_group_name_H-M 'P b a m' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2-y,z' '1/2-x,1/2+y,-z' '1/2-x,1/2+y,z' '1/2+x,1/2-y,-z' 'x,y,-z' '-x,-y,z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z Si 0.00000 0.00000 0.00000 Mg 0.08190 0.33290 0.50000 O1 0.21640 0.04480 0.50000 O2 0.39250 0.30870 0.00000