Mullite
Diffraction data computed using the structure from the paper listed below,  along with the cell parameters refined from single crystal data of R141101
      Balzar D, Ledbetter H
      American Mineralogist 78 (1993) 1192-1196
      Crystal structure and compressibility of 3:2 mullite
      _database_code_amcsd 0001618

      CELL PARAMETERS:   7.5210  7.6820  2.8950   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     0.230
            Al     0.14850   0.34070   0.50000     0.525     0.240
            Si     0.14850   0.34070   0.50000     0.342     0.240
            Al     0.26100   0.20730   0.50000     0.100     0.600
            Si     0.26100   0.20730   0.50000     0.033     0.500
            O      0.35770   0.42350   0.50000     1.000     2.120
            O      0.50000   0.00000   0.50000     0.475     2.060
            O      0.46350   0.04650   0.50000     0.198     4.530
            O      0.12650   0.21970   0.00000     1.000     2.160

            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:      8.407488267    
            The INTENSITY cut off value is   1.00

               2-THETA      INTENSITY    D-SPACING   H   K   L
                16.49         48.16        5.3742    1   1   0
                23.66          3.04        3.7605    2   0   0
                26.05         64.57        3.4207    1   2   0
                26.39        100.00        3.3775    2   1   0
                30.89         18.97        2.8950    0   0   1
                33.34         39.17        2.6871    2   2   0
                35.21         52.56        2.5487    1   1   1
                37.09         16.57        2.4240    1   3   0
                37.75          1.91        2.3833    3   1   0
                39.27         19.25        2.2940    2   0   1
                40.84         62.33        2.2098    1   2   1
                42.72         17.70        2.1166    2   3   0
                43.09          3.13        2.0994    3   2   0
                46.09          1.12        1.9695    2   2   1
                48.41          6.28        1.8802    4   0   0
                49.54          8.83        1.8400    3   1   1
                49.94          1.60        1.8263    4   1   0
                50.98          1.89        1.7914    3   3   0
                53.58          7.23        1.7104    2   4   0
                53.95          8.27        1.6995    3   2   1
                54.32         12.31        1.6888    4   2   0
                57.59         17.55        1.6004    0   4   1
                58.54          8.11        1.5769    4   0   1
                59.01          2.08        1.5653    1   4   1
                59.88          1.56        1.5447    4   1   1
                60.81         46.37        1.5233    3   3   1
                63.81          7.69        1.4587    4   2   1
                64.36         20.33        1.4475    0   0   2
                65.64          4.89        1.4223    2   5   0
                66.79          7.23        1.4006    5   2   0
                66.95          1.32        1.3977    1   1   2
                69.71          1.59        1.3490    3   4   1
                70.03          5.18        1.3435    4   4   0
                70.51         12.82        1.3356    1   5   1
                70.66          5.13        1.3331    1   2   2
                70.82          7.80        1.3305    2   1   2
                71.78          3.77        1.3151    5   1   1
                72.10          2.39        1.3100    3   5   0
                72.94          1.20        1.2970    5   3   0
                74.04          2.07        1.2803    0   6   0
                74.30         13.77        1.2765    2   5   1
                74.45          5.54        1.2744    2   2   2
                75.39         13.02        1.2608    5   2   1
                75.91          3.90        1.2535    6   0   0
                76.68          5.48        1.2428    1   3   2
                77.09          2.34        1.2372    3   1   2
                77.09          2.11        1.2371    6   1   0
                78.48          1.55        1.2187    4   4   1
                80.36          1.40        1.1948    2   3   2
                81.28          3.47        1.1836    5   3   1
                84.46          1.07        1.1470    4   0   2
                87.19          2.26        1.1180    2   6   1
                88.49          2.73        1.1049    2   4   2
                88.79          1.36        1.1019    6   2   1
                88.94          1.59        1.1004    4   5   1
                89.09          4.40        1.0990    4   2   2
                89.39          2.17        1.0961    5   4   1
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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.