Cryolite
Yang H, Ghose S, Hatch D M
Physics and Chemistry of Minerals 19 (1993) 528-544
Ferroelastic phase transition in cryolite, Na3AlF6, a mixed
fluoride perovskite: high temperature single crystal X-ray
diffraction study and symmetry analysis of the transition mechanism
Sample: T = 295 K
_database_code_amcsd 0007739
5.4139 5.6012 7.7769 90 90.183 90 P2_1/n
atom      x     y     z B(1,1) B(2,2) B(3,3)  B(1,2)  B(1,3)  B(2,3)
Al        0     0     0 .01234 .01058 .00980  .00007  .00043 -.00006
Na1       0     0    .5 .01907 .01714 .01560 -.00279 -.00015  .00219
Na2  -.0121 .4492 .2526 .02640 .02251 .02763 -.00478  .00075  .00036
F1    .1016 .0442 .2188 .02684 .02513 .01207  .00032 -.00368 -.00188
F2    .2278 .3267 .5450 .02001 .01993 .02650 -.00912  .00377 -.00025
F3    .1622 .2687 .9383 .02120 .01781 .02973 -.00597  .00077  .00602