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 = 800 K
_database_code_amcsd 0007744
5.5395 5.6378 7.9085 90 90.011 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 .02440 .02331 .02191  .00044 -.00004  .00027
Na1       0     0    .5 .04294 .04042 .03838 -.00589 -.00093  .00132
Na2  -.0075 .4645 .2510 .06223 .05993 .06305 -.00725  .00058  .00153
F1    .0888 .0342 .2179 .06940 .08527 .02738  .00166 -.00963 -.00789
F2    .2335 .3250 .5399 .04816 .05065 .06356 -.02192  .00990 -.00340
F3    .1679 .2646 .9476 .05498 .04227 .07949 -.01621  .00266  .01558