Tugtupite Antao S M, Hassan I, Parise J B American Mineralogist 89 (2004) 492-497 Tugtupite: High-temperature structures obtained from in situ synchrotron diffraction and Rietveld refinements T = 210 C _database_code_amcsd 0003454 8.63812 8.63812 8.8644 90 90 90 I-4 atom x y z Uiso Al 0 .5 .75 .0143 Be 0 .5 .25 .007 Si .0129 .2541 .4948 .0143 O1 .1502 .1368 .4437 .0134 O2 .3433 .0348 .6507 .0134 O3 .4266 .1439 .1391 .0134 Na .1582 .1969 .1826 .0336 Cl 0 0 0 .0389