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 = 373 K
_database_code_amcsd 0007740
5.4306 5.6069 7.7944 90 90.155 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 .01247 .01059 .00988  .00007  .00044 -.00006
Na1       0     0    .5 .01929 .01716 .01572 -.00281 -.00013  .00220
Na2  -.0121 .4492 .2526 .02666 .02254 .02782 -.00480  .00078  .00036
F1    .1016 .0442 .2188 .02711 .02517 .01218  .00032 -.00369 -.00189
F2    .2278 .3267 .5450 .02025 .01995 .02668 -.00917  .00381 -.00025
F3    .1622 .2687 .9383 .02144 .01783 .02993 -.00599  .00079  .00604