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 = 180 and model oxygen radius = 1
      Note: Atoms Mg, Si, and O are assigned to atomic positions for convenience
      _database_code_amcsd 0003474

      CELL PARAMETERS:    7.5260   6.9280   4.0000   90.000  110.800   90.000
      SPACE GROUP: C2/c      
      X-RAY WAVELENGTH:     1.541838
      Cell Volume:    194.968
      Density (g/cm3):      6.839
      MAX. ABS. INTENSITY / VOLUME**2:      18.46923480    
      RIR:      0.879
      RIR based on corundum from Acta Crystallographica A38 (1982) 733-739
               2-THETA      INTENSITY    D-SPACING   H   K   L   Multiplicity
                25.72         26.77        3.4640    0   2   0         2
                26.06          1.15        3.4187   -1   1   1         4
                33.48          8.31        2.6769    1   1   1         4
                35.32         50.34        2.5412    0   2   1         4
                36.40         22.75        2.4682    2   2   0         4
                38.37        100.00        2.3461   -2   2   1         4
                39.61         34.05        2.2751   -3   1   1         4
                40.61         61.14        2.2213    3   1   0         4
                41.14          5.26        2.1942    1   3   0         4
                45.56         16.87        1.9911   -1   3   1         4
                46.19          3.99        1.9653   -2   0   2         2
                47.52          1.72        1.9135   -1   1   2         4
                48.70         49.81        1.8697    0   0   2         2
                49.03         11.70        1.8580    2   2   1         4
                50.51          5.77        1.8071    1   3   1         4
                51.99          1.80        1.7589    4   0   0         2
                52.86          1.84        1.7320    0   4   0         2
                54.70         10.73        1.6780    3   1   1         4
                55.09         18.19        1.6670   -3   3   1         4
                55.88          2.23        1.6455    3   3   0         4
                55.94          2.26        1.6437   -4   2   1         4
                56.84          5.01        1.6199    1   1   2         4
                57.83         10.94        1.5945   -4   0   2         2
                58.75          8.48        1.5716    0   4   1         4
                58.89          1.88        1.5683    4   2   0         4
                59.49          3.26        1.5539    2   4   0         4
                60.86         21.21        1.5220   -2   4   1         4
                64.18          3.38        1.4512    2   0   2         2
                65.58          1.44        1.4236   -3   3   2         4
                67.98          1.60        1.3789    5   1   0         4
                68.99          4.02        1.3612    2   4   1         4
                69.09          2.46        1.3595    1   5   0         4
                69.58          1.23        1.3511    1   3   2         4
                70.34          5.17        1.3384    2   2   2         4
                72.34          4.31        1.3062    4   2   1         4
                72.78          4.92        1.2994   -2   4   2         4
                73.57          1.68        1.2874   -3   1   3         4
                73.60          1.68        1.2870   -1   1   3         4
                75.39         19.73        1.2608   -5   3   1         4
                76.57         13.51        1.2443   -2   2   3         4
                76.91          8.40        1.2397    3   1   2         4
                79.60          4.23        1.2044   -6   0   2         2
                79.86          2.89        1.2011   -3   5   1         4
                80.52          1.47        1.1929    3   5   0         4
                82.21          6.98        1.1726    6   0   0         2
                83.77         10.17        1.1547    0   6   0         2
                85.14          3.50        1.1396   -3   3   3         4
                85.16          3.50        1.1393   -1   3   3         4
                85.33          1.78        1.1376   -6   2   2         4
                89.01          2.89        1.0998   -3   5   2         4
                89.65          2.04        1.0936    4   4   1         4
================================================================================
       XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs
  For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.