Mullite
Diffraction data computed using the structure from the paper listed below,  along with the cell parameters refined from single crystal data of R141103
      Angel R J, Prewitt C T
      American Mineralogist 71 (1986) 1476-1482
      Crystal structure of mullite: A re-examination of the average structure
      _database_code_amcsd 0001059

      CELL PARAMETERS:   7.5520  7.6660  2.8760   90.000   90.000   90.000
      SPACE GROUP: Pbam      

           ATOM        X         Y         Z     OCCUPANCY  ISO(B)
            Al     0.00000   0.00000   0.00000     1.000     0.628
            Al     0.14901   0.34026   0.50000     0.560     0.680
            Si     0.14901   0.34026   0.50000     0.250     0.680
            Al     0.26247   0.20529   0.50000     0.130     0.624
            Si     0.26247   0.20529   0.50000     0.060     0.624
            Oa     0.35900   0.42180   0.50000     1.000     1.060
            Oc     0.50000   0.00000   0.50000     0.390     1.543
            Oc     0.44980   0.05050   0.50000     0.190     0.926
            Od     0.12730   0.21860   0.00000     1.000     1.095

            X-RAY WAVELENGTH:     1.541838
            BOUNDS ON TWO THETA:    5.0  90.0
            LIMITS IMPOSED ON THE INDICES ARE:  +/-  6 +/-  7 +/-  2
            MAX. ABS. INTENSITY / VOLUME**2:      7.316446948    
            The INTENSITY cut off value is   1.00

               2-THETA      INTENSITY    D-SPACING   H   K   L
                16.48         74.97        5.3799    1   1   0
                23.56          1.44        3.7760    2   0   0
                26.07         58.54        3.4180    1   2   0
                26.31        100.00        3.3874    2   1   0
                31.10         20.13        2.8760    0   0   1
                33.31         47.37        2.6900    2   2   0
                35.39         51.52        2.5363    1   1   1
                37.14         16.16        2.4205    1   3   0
                37.61          1.66        2.3917    3   1   0
                39.38         24.33        2.2879    2   0   1
                41.01         62.83        2.2006    1   2   1
                41.17          2.92        2.1924    2   1   1
                42.73         24.88        2.1163    2   3   0
                42.99          3.54        2.1041    3   2   0
                47.44          1.30        1.9165    0   4   0
                48.20          7.39        1.8880    4   0   0
                49.04          1.48        1.8576    1   4   0
                49.57         10.99        1.8389    3   1   1
                49.74          1.50        1.8332    4   1   0
                50.92          1.09        1.7933    3   3   0
                53.63          6.94        1.7090    2   4   0
                54.00         10.09        1.6982    3   2   1
                54.15         11.76        1.6937    4   2   0
                57.81         19.05        1.5948    0   4   1
                58.48          7.00        1.5783    4   0   1
                59.21          1.29        1.5604    1   4   1
                59.83          1.13        1.5459    4   1   1
                60.88         47.85        1.5217    3   3   1
                63.30          1.17        1.4692    2   4   1
                63.77         12.71        1.4594    4   2   1
                64.84         23.80        1.4380    0   0   2
                65.73          4.70        1.4206    2   5   0
                66.54          8.10        1.4052    5   2   0
                67.41          1.84        1.3892    1   1   2
                69.81          2.35        1.3472    3   4   1
                69.94          4.96        1.3450    4   4   0
                70.74         15.27        1.3318    1   5   1
                71.13          4.25        1.3255    1   2   2
                71.24          7.23        1.3237    2   1   2
                71.64          4.10        1.3173    5   1   1
                72.13          2.66        1.3094    3   5   0
                72.73          1.72        1.3002    5   3   0
                74.22          1.42        1.2777    0   6   0
                74.50         14.87        1.2737    2   5   1
                74.88          6.48        1.2682    2   2   2
                75.26         15.54        1.2626    5   2   1
                75.46          1.54        1.2598    1   6   0
                75.54          3.58        1.2587    6   0   0
                76.73          2.45        1.2420    6   1   0
                77.16          4.38        1.2363    1   3   2
                77.44          1.46        1.2324    3   1   2
                78.51          2.08        1.2183    4   4   1
                80.81          2.84        1.1894    2   3   2
                81.19          3.33        1.1848    5   3   1
                84.74          1.27        1.1440    4   0   2
                87.43          2.25        1.1155    2   6   1
                88.96          2.46        1.1003    2   4   2
                89.02          1.27        1.0997    4   5   1
                89.33          1.79        1.0967    5   4   1
                89.38          3.97        1.0962    4   2   2
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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.