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 = 473 K
_database_code_amcsd 0007741
5.4544 5.6155 7.8220 90 90.118 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 .01445 .01304 .01227 -.00018  .00065 -.00026
Na1       0     0    .5 .02344 .02155 .01941 -.00373 -.00017  .00232
Na2  -.0111 .4510 .2521 .03310 .02923 .03424 -.00608  .00130  .00122
F1    .0998 .0432 .2184 .03351 .03298 .01463  .00059 -.00371 -.00283
F2    .2286 .3266 .5442 .02516 .02502 .03253 -.01167  .00488  .00053
F3    .1630 .2678 .9398 .02678 .02256 .03817 -.00775  .00202  .00754