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 = 900 K
_database_code_amcsd 0007750
5.6333 5.6273 7.9619 90 90 90 Immm
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 .03741 .02865 .03294       0      0      0
Na1      0     0    .5 .11585 .05430 .04519       0      0      0
Na2      0    .5 .2501 .12100 .07360 .08645       0      0      0
F1       0     0 .2186 .35950 .16307 .02584       0      0      0
F2   .2335 .2160     0 .17059 .11553 .20592 -.07980      0      0