Wadsleyite Baur W H American Mineralogist 57 (1972) 709-731 Computer-simulated crystal structures of observed and hypothetical Mg2SiO4 Polymorphs of low and high density Locality: hypothetical _database_code_amcsd 0000277 8.16 11.68 5.71 90 90 90 Ibmm atom x y z Si .1303 .1255 .25 Mg1 .2297 0 .75 Mg2 .25 .25 .75 Mg3 0 .3701 0 O1 .0300 0 .25 O2 .4799 0 .75 O3 .0040 .2348 .25 O4 .2557 .3751 .0168