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 = 644 C
_database_code_amcsd 0003459
8.67908 8.67908 8.8950 90 90 90 I-4
atom     x     y     z  Uiso
Al       0    .5   .75 .0182
Be       0    .5   .25  .014
Si   .0121 .2544 .4945 .0182
O1   .1501 .1386 .4473 .0219
O2   .3427 .0324 .6521 .0219
O3   .4316 .1445 .1397 .0219
Na   .1612 .1975 .1830 .0550
Cl       0     0     0 .0681