Rumseyite
      Turner R W, Siidra O I, Krivovichev S V, Stanley C J, Spratt J
      Mineralogical Magazine 76 (2012) 1247-1255
      Rumseyite, [Pb2OF]Cl, the first naturally occurring fluoroxychloride
      mineral with the parent crystal structure for layered lead oxychlorides
      Locality: Merehead quarry, Somerset, England
      _database_code_amcsd 0019618

      CELL PARAMETERS:    4.0650   4.0650  12.6310   90.000   90.000   90.000
      SPACE GROUP: I4/mmm    
      X-RAY WAVELENGTH:     1.541838
      Cell Volume:    208.717
      Density (g/cm3):      7.714
      MAX. ABS. INTENSITY / VOLUME**2:      310.9375274    
      RIR:     13.125
      RIR based on corundum from Acta Crystallographica A38 (1982) 733-739
               2-THETA      INTENSITY    D-SPACING   H   K   L   Multiplicity
                14.02         13.67        6.3155    0   0   2         2
                22.98         56.01        3.8695    1   0   1         8
                28.26         13.35        3.1577    0   0   4         2
                30.57        100.00        2.9244    1   0   3         8
                31.11         44.89        2.8744    1   1   0         4
                42.11          1.06        2.1456    1   0   5         8
                42.53         22.73        2.1256    1   1   4         8
                42.96          3.99        2.1052    0   0   6         2
                44.58         17.72        2.0325    2   0   0         4
                46.96          1.58        1.9348    2   0   2         8
                50.74          8.31        1.7994    2   1   1        16
                53.63          5.70        1.7091    2   0   4         8
                53.99          9.34        1.6984    1   1   6         8
                55.02         21.84        1.6690    2   1   3        16
                55.74          8.22        1.6492    1   0   7         8
                63.64          2.92        1.4622    2   0   6         8
                64.88          3.25        1.4372    2   2   0         4
                72.22          1.38        1.3081    2   2   4         8
                73.41          2.65        1.2898    3   0   3         8
                73.70          2.58        1.2855    3   1   0         8
                74.02          4.08        1.2807    2   1   7        16
                80.71          2.26        1.1906    3   1   4        16
                89.29          1.50        1.0971    3   1   6        16
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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.