Pyroxene-ideal
      Thompson R M, Downs R T
      American Mineralogist 89 (2004) 614-628
      Model pyroxenes II: Structural variation as a function of tetrahedral rotation
      model with O3-O3-O3 angle = 140 and model oxygen radius = 1
      Note: Atoms Mg, Si, and O are assigned to atomic positions for convenience
      _database_code_amcsd 0003476

      CELL PARAMETERS:    7.0230   6.5100   3.7590   90.000  104.100   90.000
      SPACE GROUP: C2/c      
      X-RAY WAVELENGTH:     1.541838
      Cell Volume:    166.683
      Density (g/cm3):      8.000
      MAX. ABS. INTENSITY / VOLUME**2:      13.50431763    
      RIR:      0.550
      RIR based on corundum from Acta Crystallographica A38 (1982) 733-739
               2-THETA      INTENSITY    D-SPACING   H   K   L   Multiplicity
                27.40         25.58        3.2550    0   2   0         2
                28.33          5.16        3.1502   -1   1   1         4
                37.02         56.63        2.4281    0   2   1         4
                38.25         33.24        2.3531    2   2   0         4
                42.05         57.71        2.1487   -2   2   1         4
                42.15        100.00        2.1438    3   1   0         4
                43.78          2.46        2.0676    1   3   0         4
                43.79         41.66        2.0674   -3   1   1         4
                49.02         99.94        1.8584   -1   3   1         4
                49.51         54.00        1.8409    2   2   1         4
                50.04         55.26        1.8229    0   0   2         2
                50.72         13.60        1.7999   -2   0   2         2
                52.47          1.88        1.7440    1   3   1         4
                53.84          3.75        1.7029    4   0   0         2
                54.41         16.85        1.6863    3   1   1         4
                57.18         13.89        1.6109    1   1   2         4
                58.43         16.35        1.5796   -3   1   2         4
                58.61          4.41        1.5751   -2   2   2         4
                60.16         28.25        1.5381   -3   3   1         4
                61.20          9.60        1.5145   -4   2   1         4
                61.45          2.04        1.5088    4   2   0         4
                62.50          8.25        1.4861    0   4   1         4
                63.34          5.90        1.4684    2   4   0         4
                63.48         10.66        1.4655    2   0   2         2
                65.23          6.91        1.4303   -4   0   2         2
                66.05          9.26        1.4146   -2   4   1         4
                70.47          5.72        1.3363    2   2   2         4
                70.64          2.61        1.3334    5   1   0         4
                71.78         19.56        1.3151    2   4   1         4
                72.83          1.57        1.2986    4   2   1         4
                75.89          6.39        1.2537    3   1   2         4
                78.06          2.20        1.2243   -5   1   2         4
                81.58          6.52        1.1801   -3   1   3         4
                81.65          2.99        1.1792   -4   4   1         4
                82.28         18.59        1.1717   -5   3   1         4
                83.08          9.24        1.1625   -2   2   3         4
                85.24          1.73        1.1385    0   2   3         4
                85.54         10.33        1.1352    6   0   0         2
                86.09          6.28        1.1295    3   5   0         4
                87.20          2.28        1.1179   -3   5   1         4
                87.37          5.02        1.1161    4   0   2         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.