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 = 709 C _database_code_amcsd 0003460 8.68613 8.68613 8.9006 90 90 90 I-4 atom x y z Uiso Al 0 .5 .75 .0187 Be 0 .5 .25 .013 Si .0119 .2541 .4949 .0187 O1 .1496 .1380 .4483 .0228 O2 .3433 .0325 .6522 .0228 O3 .4327 .1456 .1396 .0228 Na .1618 .1978 .1831 .0571 Cl 0 0 0 .0731