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 = 113 C _database_code_amcsd 0003453 8.63144 8.63144 8.8598 90 90 90 I-4 atom x y z Uiso Al 0 .5 .75 .0135 Be 0 .5 .25 .005 Si .0131 .2540 .4949 .0135 O1 .1502 .1366 .4433 .0120 O2 .3436 .0352 .6506 .0120 O3 .4257 .1439 .1390 .0120 Na .1577 .1969 .1824 .0301 Cl 0 0 0 .0344