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 Model II Locality: hypothetical _database_code_amcsd 0000281 10.05 5.75 4.87 90 90.0 90 C2/m atom x y z Si .3330 0 .8987 Mg1 0 0 0 Mg2 .5 0 .5 Mg3 .25 .25 .5 O1 .8194 0 .2220 O2 .3341 0 .2353 O3 .0908 .2703 .2253