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 = 890 K
      _database_code_amcsd 0007749

      CELL PARAMETERS:    5.6323   5.6270   7.9580   90.000   90.000   90.000
      SPACE GROUP: Immm      
      X-RAY WAVELENGTH:     1.541838
      Cell Volume:    252.213
      Density (g/cm3):      2.764
      MAX. ABS. INTENSITY / VOLUME**2:      4.239166581    
      RIR:      0.499
      RIR based on corundum from Acta Crystallographica A38 (1982) 733-739
               2-THETA      INTENSITY    D-SPACING   H   K   L   Multiplicity
                19.31         17.75        4.5974    1   0   1         4
                19.32         35.25        4.5945    0   1   1         4
                22.33         66.14        3.9808    1   1   0         4
                22.34         23.21        3.9790    0   0   2         2
                31.77         33.19        2.8161    2   0   0         2
                31.80        100.00        2.8142    1   1   2         8
                31.81         35.35        2.8135    0   2   0         2
                37.48          1.20        2.3998    1   2   1         8
                39.19          3.48        2.2987    2   0   2         4
                39.22          3.00        2.2972    0   2   2         4
                45.58         32.34        1.9904    2   2   0         4
                45.60         15.42        1.9895    0   0   4         2
                51.30          2.00        1.7809    3   1   0         4
                51.33          2.00        1.7801    2   2   2         8
                51.34          3.52        1.7796    1   1   4         8
                51.34          2.00        1.7796    1   3   0         4
                56.62          7.25        1.6255    3   1   2         8
                56.65          4.46        1.6249    2   0   4         4
                56.66          7.22        1.6245    1   3   2         8
                56.66          4.52        1.6244    0   2   4         4
                66.39          1.01        1.4081    4   0   0         2
                66.44          3.87        1.4071    2   2   4         8
                75.53          1.18        1.2588    3   3   2         8
                75.56          1.23        1.2583    1   1   6         8
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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.