Sillimanite Winter J K, Ghose S American Mineralogist 64 (1979) 573-586 Thermal expansion and high-temperature crystal chemistry of the Al2SiO5 polymorphs T = 800 deg C _database_code_amcsd 0000726 7.4998 7.7255 5.7978 90 90 90 Pbnm atom x y z B(1,1) B(2,2) B(3,3) B(1,2) B(1,3) B(2,3) Al1 0 0 0 0.0040 0.0053 0.0079 .0000 -.0002 -.0001 Al2 .1412 .3461 .25 0.0043 0.0054 0.0085 -.0003 0 0 Si .1523 .3410 .75 0.0037 0.0047 0.0080 -.0006 0 0 O1 .3594 .4100 .75 0.0040 0.0072 0.0107 -.0019 0 0 O2 .3570 .4352 .25 0.0040 0.0073 0.0100 -.0017 0 0 O3 .4777 .0005 .75 0.0103 0.0099 0.0215 -.0057 0 0 O4 .1247 .2250 .5145 0.0078 0.0056 0.0083 -.0019 -.0004 -.0002