Jarosite
Diffraction data computed using the structure from the paper listed below, 
along with the cell parameters refined from single crystal data of R070493
      Basciano L C, Peterson R C
      American Mineralogist 92 (2007) 1464-1473
      Jarosite - hydronium jarosite solid solution series with
      full iron occupancy: Mineralogy and crystal chemistry
      Locality: synthetic
      Sample: E

      CELL PARAMETERS:   7.3610  7.3610 17.1900   90.000   90.000  120.000
      SPACE GROUP: R-3m      

           ATOM        X         Y         Z     OCCUPANCY  ISO(B)
            K      0.00000   0.00000   0.00000     0.510     1.100
            H      0.00000   0.00000   0.00000     0.490     1.100
            Fe     0.16667  -0.16667  -0.16667     1.000     1.980
            S      0.00000   0.00000   0.30890     1.000     1.390
            O      0.00000   0.00000   0.39400     1.000     3.200
            O      0.22240  -0.22240  -0.05570     1.000     2.500
            O      0.12660  -0.12660   0.13580     1.000     0.930
            H      0.17700  -0.17700   0.11050     1.000     2.000

            X-RAY WAVELENGTH:     1.541838
            BOUNDS ON TWO THETA:    0.0  90.0
            LIMITS IMPOSED ON THE INDICES ARE:  +/-  5 +/-  5 +/- 15
            MAX. ABS. INTENSITY / VOLUME**2:      17.09974144    
            The INTENSITY cut off value is   1.00

               2-THETA      INTENSITY    D-SPACING   H   K   L
                14.82         20.61        5.9770    1   0   1
                15.46         40.29        5.7300    0   0   3
                17.32         96.08        5.1202    0   1   2
                24.18          6.31        3.6805    1   1   0
                24.99          7.47        3.5634    1   0   4
                28.48         89.02        3.1340    0   2   1
                28.83        100.00        3.0967    1   1   3
                29.52          2.45        3.0260    0   1   5
                29.90         10.04        2.9885    2   0   2
                31.22         18.79        2.8650    0   0   6
                35.05         21.46        2.5601    0   2   4
                38.52          2.31        2.3374    2   0   5
                39.32         30.57        2.2916    1   0   7
                45.53         30.46        1.9923    0   3   3
                45.53          1.44        1.9923    3   0   3
                46.69         11.34        1.9453    0   2   7
                47.61          6.12        1.9100    0   0   9
                49.53         32.32        1.8403    2   2   0
                51.28          4.28        1.7817    2   0   8
                52.21          6.51        1.7521    2   2   3
                52.87          5.22        1.7318    3   1   2
                53.26          1.62        1.7199    2   1   7
                54.10          1.69        1.6953    1   1   9
                56.26          3.91        1.6351    1   3   4
                57.46          5.67        1.6037    1   2   8
                58.13          4.72        1.5869    4   0   1
                58.72          3.25        1.5723    3   1   5
                58.94          5.26        1.5670    0   4   2
                59.72         15.37        1.5484    2   2   6
                61.27         18.87        1.5130    0   2  10
                62.12          5.48        1.4943    4   0   4
                63.88          1.56        1.4572    3   2   1
                64.44          3.20        1.4459    0   4   5
                64.65          3.35        1.4418    2   3   2
                65.00          2.51        1.4349    1   3   7
                65.74          2.76        1.4205    0   3   9
                66.65          3.41        1.4032    2   0  11
                67.67          1.21        1.3845    3   2   4
                69.54          2.82        1.3518    1   4   3
                69.54          4.37        1.3518    4   1   3
                70.43          2.42        1.3369    4   0   7
                71.14          3.09        1.3252    2   2   9
                73.09          1.32        1.2947    1   0  13
                75.69          5.36        1.2565    3   2   7
                82.54          2.69        1.1687    4   0  10
                83.37          3.15        1.1592    2   1  13
                85.38          1.32        1.1369    4   2   5
                86.00          1.45        1.1304    2   2  12
                87.40          1.55        1.1158    0   4  11
                89.61          1.03        1.0940    1   2  14
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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.