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 = 820 K
Note: beta angle has been altered in order to reproduce bond lengths
_database_code_amcsd 0007745
5.5443 5.6391 7.9127 90 90.098 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 .02405 .02436 .02194  .00052 -.00013 -.00005
Na1       0     0    .5 .04382 .04116 .04030 -.00662 -.00035  .00070
Na2  -.0074 .4657 .2511 .06227 .06293 .06527 -.00784  .00090  .00238
F1    .0873 .0331 .2177 .07062 .09145 .02857  .00344 -.00926 -.00786
F2    .2341 .3247 .5399 .04837 .05190 .06694 -.02314  .01093 -.00289
F3    .1680 .2642 .9486 .05589 .04528 .07890 -.01709  .00129  .01477