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

      CELL PARAMETERS:    5.5732   5.6414   7.9365   90.000   89.990   90.000
      SPACE GROUP: P2_1/n    
      X-RAY WAVELENGTH:     1.541838
      Cell Volume:    249.529
      Density (g/cm3):      2.794
      MAX. ABS. INTENSITY / VOLUME**2:      3.976262577    
      RIR:      0.463
      RIR based on corundum from Acta Crystallographica A38 (1982) 733-739
               2-THETA      INTENSITY    D-SPACING   H   K   L   Multiplicity
                19.30         41.83        4.5981    0   1   1         4
                19.46         22.44        4.5613    1   0   1         2
                19.46         16.13        4.5606   -1   0   1         2
                22.40         26.14        3.9683    0   0   2         2
                22.42         58.74        3.9647    1   1   0         4
                25.11          1.32        3.5470    1   1   1         4
                25.11          2.22        3.5466   -1   1   1         4
                31.72         31.82        2.8207    0   2   0         2
                31.91         48.19        2.8049    1   1   2         4
                31.91         51.81        2.8046   -1   1   2         4
                32.12         22.50        2.7866    2   0   0         2
                35.68          4.34        2.5167    1   2   0         4
                35.95          9.82        2.4984    2   1   0         4
                37.49          4.58        2.3990    1   2   1         4
                37.49          4.27        2.3989   -1   2   1         4
                37.63          8.69        2.3901    1   0   3         2
                37.64          9.85        2.3898   -1   0   3         2
                37.75          6.81        2.3832    2   1   1         4
                37.75          5.73        2.3830   -2   1   1         4
                39.18         13.66        2.2991    0   2   2         4
                39.51          3.85        2.2807    2   0   2         2
                39.52          4.07        2.2803   -2   0   2         2
                41.01          3.76        2.2007    1   1   3         4
                41.02          1.28        2.2005   -1   1   3         4
                42.53          2.24        2.1254    1   2   2         4
                42.54          4.24        2.1253   -1   2   2         4
                42.77          1.66        2.1141   -2   1   2         4
                45.73         25.00        1.9841    0   0   4         2
                45.77         48.02        1.9824    2   2   0         4
                47.10          1.01        1.9296    0   2   3         4
                50.02          1.04        1.8235    1   2   3         4
                50.23          1.04        1.8163   -2   1   3         4
                50.45          1.04        1.8089    3   0   1         2
                51.27          4.39        1.7818    1   3   0         4
                51.50          4.83        1.7744    1   1   4         4
                51.54          4.68        1.7733   -2   2   2         4
                51.81          1.37        1.7645    3   1   0         4
                52.65          2.48        1.7385   -1   3   1         4
                53.17          1.35        1.7225    3   1   1         4
                56.62          3.05        1.6255    1   3   2         4
                56.63          5.95        1.6254   -1   3   2         4
                56.72          6.62        1.6228    0   2   4         4
                56.97          5.07        1.6164    2   0   4         2
                56.98          1.16        1.6161   -2   0   4         2
                57.12          4.84        1.6124    3   1   2         4
                57.13          9.00        1.6122   -3   1   2         4
                60.53          1.53        1.5295   -2   3   1         4
                60.66          1.11        1.5267    1   0   5         2
                60.84          1.15        1.5226   -3   2   1         4
                66.27          1.91        1.4103    0   4   0         2
                66.69          3.34        1.4025    2   2   4         4
                66.70          3.17        1.4023   -2   2   4         4
                67.19          1.15        1.3933    4   0   0         2
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       XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs
  For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.