Schwartzembergite
Diffraction data computed using the structute from the paper listed below,
along with the cell parameters refined from single crystal data of R070429
      Welch M D, Hawthorne F C, Cooper M A, Kyser T K
      The Canadian Mineralogist 39 (2001) 785-795
      Trivalent iodine in the crystal structure of schwartzembergite, Pb5IO6H2Cl3

      CELL PARAMETERS:   3.9630  3.9630 12.5190   90.000   90.000   90.000
      SPACE GROUP: I4/mmm    

           ATOM        X         Y         Z     OCCUPANCY  ISO(B)
            Pb     0.00000   0.00000   0.14210     0.833     0.184
            I      0.00000   0.00000   0.18500     0.167     0.139
            Cl     0.00000   0.00000   0.50000     1.000     0.232
            O      0.50000   0.00000   0.25000     1.000     0.247

            X-RAY WAVELENGTH:     1.541838
            BOUNDS ON TWO THETA:    0.0  90.0
            LIMITS IMPOSED ON THE INDICES ARE:  +/-  3 +/-  3 +/- 11
            MAX. ABS. INTENSITY / VOLUME**2:      364.1709761    
            The INTENSITY cut off value is   1.00

               2-THETA      INTENSITY    D-SPACING   H   K   L
                14.15         11.00        6.2595    0   0   2
                23.55         50.73        3.7782    1   0   1
                28.52         12.37        3.1298    0   0   4
                31.12        100.00        2.8736    1   0   3
                31.94         47.71        2.8023    1   1   0
                42.72          1.91        2.1167    1   0   5
                43.34         27.03        2.0877    1   1   4
                43.37          4.04        2.0865    0   0   6
                45.79         23.87        1.9815    2   0   0
                48.17          1.97        1.8891    2   0   2
                52.12         12.97        1.7548    2   1   1
                54.84          9.16        1.6742    2   0   4
                54.86         12.35        1.6735    1   1   6
                56.40         36.69        1.6313    2   1   3
                56.45         11.57        1.6301    1   0   7
                59.03          1.63        1.5649    0   0   8
                64.41          1.08        1.4466    2   1   5
                64.90          5.04        1.4368    2   0   6
                66.76          7.50        1.4011    2   2   0
                68.70          2.60        1.3663    1   1   8
                71.86          2.53        1.3137    3   0   1
                74.15          3.93        1.2788    2   2   4
                75.49          7.75        1.2594    3   0   3
                75.52          9.94        1.2589    2   1   7
                75.93          8.30        1.2532    3   1   0
                77.77          2.84        1.2281    2   0   8
                83.00          8.08        1.1634    3   1   4
                83.02          2.63        1.1632    2   2   6
                84.82          2.12        1.1430    1   1  10
                89.51          3.00        1.0949    3   2   1
                89.62          3.51        1.0939    1   0  11
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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.