Tridymite
      Kihara K, Matsumoto T, Imamura M
      Zeitschrift fur Kristallographie 177 (1986) 27-38
      Structural change of orthorhombic-I tridymite with temperature:
      A study based on second-order thermal-vibrational parameters
      Note: hexagonal Gibbs model, T = 693 K
      Locality: synthetic refractory silica brick
      _database_code_amcsd 0020937

      CELL PARAMETERS:    5.0470   5.0470   8.2620   90.000   90.000  120.000
      SPACE GROUP: P6_3/mmc  
      X-RAY WAVELENGTH:     1.541838
      Cell Volume:    182.256
      Density (g/cm3):      2.189
      MAX. ABS. INTENSITY / VOLUME**2:      18.74809746    
      RIR:      2.788
      RIR based on corundum from Acta Crystallographica A38 (1982) 733-739
               2-THETA      INTENSITY    D-SPACING   H   K   L   Multiplicity
                20.32        100.00        4.3708    1   0   0         6
                21.51         53.04        4.1310    0   0   2         2
                23.02         53.89        3.8635    1   0   1        12
                29.76         17.10        3.0023    1   0   2        12
                35.58         21.19        2.5235    1   1   0         6
                38.64         11.15        2.3300    1   0   3        12
                41.95          2.02        2.1535    1   1   2        12
                42.80          5.57        2.1128    2   0   1        12
                43.83          2.02        2.0655    0   0   4         2
                47.04          1.09        1.9317    2   0   2        12
                53.53          3.78        1.7119    2   0   3        12
                55.63          3.89        1.6520    2   1   0        12
                56.83          2.94        1.6200    2   1   1        24
                59.84          4.74        1.5456    1   0   5        12
                60.34          1.77        1.5339    2   1   2        24
                63.89          2.14        1.4569    3   0   0         6
                65.94          3.43        1.4167    2   1   3        24
                71.59          1.99        1.3180    2   0   5        12
                75.32          1.75        1.2617    2   2   0         6
                79.25          1.14        1.2088    1   1   6        12
                79.41          1.07        1.2067    2   2   2        12
                82.58          1.98        1.1683    2   1   5        24
                88.03          1.06        1.1095    3   1   3        24
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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.