Prehnite
Papike J J, Zoltai T
American Mineralogist 52 (1967) 974-984
Ordering of tetrahedral aluminium in prehnite, Ca2(Al,Fe)[Si3AlO10](OH)2
_database_code_amcsd 0000157
4.646 5.483 18.486 90 90 90 Pncm
atom     x     y     z occ Biso
Ca       0    .5 .0992      .41
Al       0     0     0      .26
Si1     .5     0 .1195      .25
Si2  .1895   .25   .25  .5  .20
Al2  .1895   .25   .25  .5  .20
O1   .7511 .1323 .0739      .45
O2   .3686 .2130 .1716      .59
O3       0     0 .2687     1.55
OH   .2054 .3018     0      .68