Wadeite
Diffraction data computed using the structure from the paper listed below, 
along with the cell parameters refined from single crystal data of R130537
      Xu H, Navrotsky A, Balmer M L, Su Y
      Physics and Chemistry of Minerals 32 (2005) 426-435
      Crystal-chemical and energetic systematics of wadeite-type phases
      A2BSi3O9 (A = K, Cs; B = Si, Ti, Zr)
      _database_code_amcsd 0008975

      CELL PARAMETERS:   6.9255  6.9255 10.1885   90.000   90.000  120.000
      SPACE GROUP: P6_3/m    

           ATOM        X         Y         Z     OCCUPANCY  ISO(B)
            K      0.33333   0.66667   0.05840     1.000     1.563
            Zr     0.00000   0.00000   0.00000     1.000     0.553
            Si     0.38920   0.25840   0.25000     1.000     0.458
            O      0.48800   0.09000   0.25000     1.000     0.884
            O      0.25850   0.24290   0.11770     1.000     0.884

            X-RAY WAVELENGTH:     1.541838
            BOUNDS ON TWO THETA:    5.0  90.0
            LIMITS IMPOSED ON THE INDICES ARE:  +/-  5 +/-  5 +/-  9
            MAX. ABS. INTENSITY / VOLUME**2:      26.62931617    
            The INTENSITY cut off value is   1.00

               2-THETA      INTENSITY    D-SPACING   H   K   L
                14.77         39.82        5.9977    1   0   0
                17.16         11.72        5.1686    1   0   1
                22.90         49.93        3.8827    1   0   2
                25.73         26.73        3.4627    1   1   0
                27.20         20.25        3.2786    1   1   1
                30.24         38.93        2.9553    1   0   3
                31.09         24.51        2.8768    2   0   1
                31.23        100.00        2.8638    1   1   2
                34.71          7.45        2.5843    2   0   2
                35.24          6.88        2.5471    0   0   4
                37.08          1.63        2.4247    1   1   3
                38.40          2.46        2.3445    1   0   4
                39.76          5.18        2.2669    1   2   0
                40.78         14.11        2.2128    1   2   1
                43.71          3.89        2.0711    2   1   2
                44.14         10.48        2.0518    1   1   4
                45.36         16.47        1.9992    3   0   0
                46.79         12.83        1.9414    2   0   4
                48.27          2.95        1.8855    1   2   3
                48.94         21.18        1.8610    3   0   2
                52.88          7.47        1.7314    2   2   0
                54.16         15.85        1.6934    1   2   4
                54.16          8.67        1.6934    2   1   4
                54.44          6.43        1.6854    2   0   5
                55.22          5.82        1.6635    1   3   0
                56.01          1.98        1.6417    3   1   1
                56.10          7.79        1.6393    2   2   2
                56.31          7.60        1.6339    1   0   6
                58.36          5.96        1.5813    3   1   2
                58.71          1.64        1.5727    3   0   4
                60.75          3.39        1.5246    1   1   6
                61.16          3.90        1.5154    2   1   5
                61.16          1.57        1.5154    1   2   5
                61.88          1.85        1.4994    4   0   0
                62.14          5.96        1.4939    3   1   3
                62.90          5.33        1.4776    2   0   6
                64.82          3.79        1.4384    4   0   2
                65.15          6.13        1.4319    2   2   4
                66.05          1.75        1.4144    1   0   7
                67.22          2.56        1.3928    1   3   4
                68.39          1.21        1.3717    4   0   3
                69.12          3.65        1.3591    2   1   6
                70.14          1.17        1.3418    1   1   7
                70.95          2.70        1.3284    3   2   2
                70.95          1.93        1.3284    2   3   2
                72.18          2.18        1.3088    1   4   0
                72.18          7.37        1.3088    4   1   0
                73.49          1.21        1.2886    1   3   5
                74.39          5.25        1.2753    3   2   3
                74.50          1.61        1.2736    0   0   8
                74.91          7.43        1.2676    1   4   2
                76.46          3.13        1.2458    1   0   8
                79.11          1.08        1.2106    3   2   4
                79.11          1.09        1.2106    2   3   4
                80.90          3.78        1.1883    3   1   6
                82.24          1.37        1.1722    2   0   8
                82.94          4.96        1.1641    4   1   4
                85.07          1.63        1.1403    2   3   5
                86.44          1.06        1.1257    3   3   2
                86.61          2.18        1.1240    4   0   6
                87.94          1.25        1.1103    2   1   8
                87.94          3.71        1.1103    1   2   8
                89.46          1.44        1.0954    3   1   7
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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.