Matlockite
Diffraction data computed using the structure from the paper listed below, along with the cell parameters refined from single crystal data of R140538
      Nieuwenkamp W, Bijvoet J
      Zeitschrift fur Kristallographie 81 (1932) 469-473
      Die Kristallstruktur von Bleifluochlorid Pb F Cl
      _cod_database_code 1011046
      _database_code_amcsd 0017948

      CELL PARAMETERS:   4.0870  4.0870  7.2020   90.000   90.000   90.000
      SPACE GROUP: P4/nmm    

           ATOM        X         Y         Z     OCCUPANCY  ISO(B)
            Pb     0.00000   0.50000   0.20500     1.000     1.500
            Cl     0.00000   0.50000   0.65000     1.000     1.000
            F      0.50000   0.50000   0.00000     1.000     1.000

            X-RAY WAVELENGTH:     1.541838
            BOUNDS ON TWO THETA:    5.0  90.0
            LIMITS IMPOSED ON THE INDICES ARE:  +/-  3 +/-  3 +/-  6
            MAX. ABS. INTENSITY / VOLUME**2:      298.3879941    
            The INTENSITY cut off value is   1.00

               2-THETA      INTENSITY    D-SPACING   H   K   L
                12.29         14.40        7.2020    0   0   1
                24.72         25.24        3.6010    0   0   2
                25.05        100.00        3.5545    1   0   1
                30.94         51.43        2.8899    1   1   0
                33.16         36.35        2.7019    1   0   2
                37.46          3.04        2.4007    0   0   3
                40.00         41.75        2.2539    1   1   2
                43.73         16.39        2.0700    1   0   3
                44.33         24.54        2.0435    2   0   0
                46.18          2.01        1.9659    2   0   1
                49.35         10.19        1.8466    1   1   3
                51.41         12.42        1.7773    2   0   2
                51.59         25.86        1.7716    2   1   1
                55.79         14.46        1.6477    1   0   4
                56.46         13.20        1.6298    2   1   2
                59.40          3.07        1.5561    2   0   3
                64.03          9.03        1.4542    2   1   3
                64.49          6.70        1.4450    2   2   0
                64.72          2.45        1.4404    0   0   5
                70.18          4.31        1.3410    2   2   2
                70.33          4.42        1.3386    3   0   1
                73.24          6.55        1.2924    3   1   0
                73.45          4.58        1.2891    1   1   5
                73.89         10.78        1.2827    2   1   4
                74.46          2.50        1.2742    3   0   2
                77.03          1.28        1.2380    2   2   3
                78.65          8.19        1.2164    3   1   2
                81.18          2.00        1.1848    3   0   3
                81.81          4.33        1.1773    2   0   5
                84.04          2.85        1.1517    1   0   6
                85.29          3.00        1.1380    3   1   3
                87.02          4.39        1.1197    3   2   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.