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 = 880 K _database_code_amcsd 0007748 5.5732 5.6414 7.9365 90 89.990 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 .02643 .02647 .02491 .00150 .00038 -.00036 Na1 0 0 .5 .05031 .04616 .04514 -.00526 .00017 .00036 Na2 -.0060 .4715 .2517 .07099 .07352 .07286 -.00949 .00010 .00177 F1 .0816 .0295 .2172 .08614 .10322 .03367 .00525 -.01038 -.00778 F2 .2374 .3224 .5388 .05455 .06488 .08424 -.02609 .01380 -.00251 F3 .1704 .2628 .9521 .06731 .05133 .09447 -.02153 -.00110 .01937