Pyroxene-ideal
      Thompson R M, Downs R T
      American Mineralogist 88 (2003) 653-666
      Model pyroxenes I: Ideal pyroxene topologies
      Pyroxene #3a based on stacking sequence ABABCACABCBC
      Note: Atoms Mg, Si, and O are assigned to atomic positions just for convenience.
      _database_code_amcsd 0002998

      CELL PARAMETERS:    6.6333   6.0000   3.4641   90.000  100.025   90.000
      SPACE GROUP: P2/c      
      X-RAY WAVELENGTH:     1.541838
      Cell Volume:    135.764
      Density (g/cm3):      9.821
      MAX. ABS. INTENSITY / VOLUME**2:      19.22468184    
      RIR:      0.637
      RIR based on corundum from Acta Crystallographica A38 (1982) 733-739
               2-THETA      INTENSITY    D-SPACING   H   K   L   Multiplicity
                20.10          1.13        4.4188    1   1   0         4
                27.31          3.82        3.2660    2   0   0         2
                29.78          8.12        3.0000    0   2   0         2
                30.14         13.93        2.9654    0   1   1         4
                31.18         14.81        2.8685   -1   1   1         4
                40.84         26.80        2.2094    2   2   0         4
                40.84         42.18        2.2094   -1   2   1         4
                44.00          8.97        2.0580    1   2   1         4
                44.25         88.45        2.0467    3   1   0         4
                44.25         11.55        2.0467    2   1   1         4
                46.25         36.41        1.9629   -2   2   1         4
                47.95          5.91        1.8974   -3   1   1         4
                51.89          7.38        1.7621    2   2   1         4
                53.08         25.70        1.7253    0   3   1         4
                53.08         12.85        1.7253   -1   0   2         2
                55.20         13.13        1.6641   -3   2   1         4
                56.06          6.31        1.6406    3   1   1         4
                56.06         15.55        1.6406    0   1   2         4
                56.34          4.05        1.6330    4   0   0         2
                56.34         26.88        1.6330    1   3   1         4
                56.34         13.44        1.6330   -2   0   2         2
                58.24         28.32        1.5842   -2   3   1         4
                58.24         14.16        1.5842    1   0   2         2
                58.58          3.61        1.5757   -2   1   2         4
                60.44          2.74        1.5317   -4   1   1         4
                60.44         15.09        1.5317    1   1   2         4
                62.06          1.48        1.4956   -1   2   2         4
                62.66          1.63        1.4827    0   2   2         4
                63.12          1.13        1.4729    2   3   1         4
                65.22          3.31        1.4304   -3   1   2         4
                66.07         14.78        1.4142   -3   3   1         4
                66.07          7.39        1.4142    2   0   2         2
                68.12          6.70        1.3765    2   1   2         4
                68.88          4.88        1.3631    2   4   0         4
                68.88          8.04        1.3631   -1   4   1         4
                69.83          1.73        1.3469    4   1   1         4
                71.15          1.95        1.3252    1   4   1         4
                71.33          2.53        1.3222   -3   2   2         4
                72.83          8.02        1.2987   -2   4   1         4
                72.89          4.78        1.2978   -4   0   2         2
                72.89          9.56        1.2978    3   3   1         4
                74.12          1.34        1.2792    2   2   2         4
                74.30          2.38        1.2765    5   1   0         4
                75.77          4.38        1.2554    4   2   1         4
                76.75          9.84        1.2418   -4   3   1         4
                76.75          4.92        1.2418    3   0   2         2
                77.23          1.82        1.2352    2   4   1         4
                79.95          4.14        1.2000   -3   4   1         4
                80.67          1.87        1.1911   -4   2   2         4
                84.42          1.00        1.1474    3   2   2         4
                85.37          1.64        1.1371    4   3   1         4
                87.27          2.85        1.1172   -5   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.