Mg2SiO4 Baur W H American Mineralogist 57 (1972) 709-731 Computer-simulated crystal structures of observed and hypothetical Mg2SiO4 polymorphs of low and high density Sr2PbO4 structure Locality: hypothetical _database_code_amcsd 0000283 4.98 8.85 2.75 90 90 90 Pbam atom x y z Si 0 0 0 Mg .0819 .3329 .5 O1 .2164 .0448 .5 O2 .3925 .3087 0