Marshite
      Diffraction data computed using the structure from the paper listed below, 
      along with the cell parameters refined from single crystal data of R100001
      Cooper M A, Hawthorne F C
      The Canadian Mineralogist 35 (1997) 785-786
      A note on the crystal structure of marshite

      CELL PARAMETERS:   6.0590  6.0590  6.0590   90.000   90.000   90.000
      SPACE GROUP: F-43m     

           ATOM        X         Y         Z     OCCUPANCY  ISO(B)
            Cu     0.25000   0.25000   0.25000     1.000     2.653
            I      0.00000   0.00000   0.00000     1.000     1.532

            X-RAY WAVELENGTH:     1.541838
            BOUNDS ON TWO THETA:    5.0  90.0
            LIMITS IMPOSED ON THE INDICES ARE:  +/-  5 +/-  5 +/-  5
            MAX. ABS. INTENSITY / VOLUME**2:      257.0525611    
            The INTENSITY cut off value is   1.00

               2-THETA      INTENSITY    D-SPACING   H   K   L
                25.46        100.00        3.4982    1   1   1
                29.48          8.27        3.0295    2   0   0
                42.19         61.49        2.1422    2   2   0
                49.92         38.13        1.8269    3   1   1
                52.30          2.18        1.7491    2   2   2
                61.19          8.04        1.5148    4   0   0
                67.37         12.60        1.3900    3   3   1
                69.36          2.84        1.3548    4   2   0
                77.12         13.11        1.2368    4   2   2
                82.77          5.94        1.1661    5   1   1
                82.77          1.98        1.1661    3   3   3
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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.