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 = 220 and model oxygen radius = 1
      Note: Atoms Mg, Si, and O are assigned to atomic positions for convenience
      _database_code_amcsd 0003472

      CELL PARAMETERS:    7.5650   6.5100   3.7590   90.000  115.800   90.000
      SPACE GROUP: C2/c      
      X-RAY WAVELENGTH:     1.541838
      Cell Volume:    166.670
      Density (g/cm3):      8.000
      MAX. ABS. INTENSITY / VOLUME**2:      25.42090875    
      RIR:      1.035
      RIR based on corundum from Acta Crystallographica A38 (1982) 733-739
               2-THETA      INTENSITY    D-SPACING   H   K   L   Multiplicity
                27.40         13.59        3.2550    0   2   0         2
                27.45         21.02        3.2496   -1   1   1         4
                37.09          7.37        2.4237    1   1   1         4
                38.25         17.66        2.3530    2   2   0         4
                38.37          8.74        2.3460    0   2   1         4
                39.45         16.38        2.2844   -3   1   1         4
                39.53        100.00        2.2798   -2   2   1         4
                42.15         53.12        2.1437    3   1   0         4
                43.78          1.31        2.0676    1   3   0         4
                48.55          1.98        1.8751   -2   0   2         2
                51.61          9.00        1.7709   -1   1   2         4
                53.72          1.71        1.7064    2   2   1         4
                53.84          1.99        1.7027    4   0   0         2
                54.21         44.12        1.6921    0   0   2         2
                55.02          7.98        1.6690    1   3   1         4
                56.65          1.57        1.6248   -2   2   2         4
                56.78         33.31        1.6214   -3   3   1         4
                57.72          4.09        1.5971   -4   0   2         2
                59.81          5.77        1.5463    3   1   1         4
                61.46          1.08        1.5088    4   2   0         4
                63.34          3.13        1.4684    2   4   0         4
                64.23         20.31        1.4501   -2   4   1         4
                70.65          1.39        1.3333    5   1   0         4
                72.37          7.91        1.3057    2   0   2         2
                73.83          1.95        1.2836    3   3   1         4
                76.84         27.31        1.2406   -5   3   1         4
                77.62          1.83        1.2300   -1   5   1         4
                77.69          1.55        1.2291   -2   4   2         4
                78.40          1.20        1.2198   -6   0   2         2
                78.78          4.57        1.2148    4   2   1         4
                81.55          3.47        1.1804   -1   1   3         4
                83.07          4.93        1.1626   -2   2   3         4
                84.90          1.07        1.1422   -6  -2   2         4
                85.11          1.06        1.1399   -4   4   2         4
                85.55          5.49        1.1352    6   0   0         2
                86.09          3.34        1.1294    3   5   0         4
                86.74          5.31        1.1227    3   1   2         4
================================================================================
       XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs
  For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.