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 = 596 C _database_code_amcsd 0003458 8.67339 8.67339 8.8904 90 90 90 I-4 atom x y z Uiso Al 0 .5 .75 .0175 Be 0 .5 .25 .013 Si .0122 .2544 .4946 .0175 O1 .1501 .1384 .4467 .0208 O2 .3427 .0329 .6520 .0208 O3 .4310 .1444 .1396 .0208 Na .1606 .1974 .1830 .0518 Cl 0 0 0 .0638