Sillimanite
Winter J K, Ghose S
American Mineralogist 64 (1979) 573-586
Thermal expansion and high-temperature crystal chemistry of the Al2SiO5 polymorphs
T = 600 deg C
_database_code_amcsd 0000725
7.4967 7.7136 5.7921 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 0.0031 0.0043 0.0068  .0000 -.0001 -.0001
Al2  .1414 .3459   .25 0.0034 0.0045 0.0074 -.0002      0      0
Si   .1525 .3408   .75 0.0030 0.0040 0.0067 -.0005      0      0
O1   .3597 .4100   .75 0.0033 0.0063 0.0084 -.0016      0      0
O2   .3568 .4349   .25 0.0033 0.0062 0.0086 -.0012      0      0
O3   .4771 .0013   .75 0.0081 0.0080 0.0183 -.0047      0      0
O4   .1247 .2245 .5142 0.0061 0.0048 0.0073 -.0016 -.0003  .0000