Americium
      Wyckoff R W G
      Crystal Structures 1 (1963) 7-83
      Second edition. Interscience Publishers, New York, New York
      Double hexagonal closest packed, dhcp, structure
      _database_code_amcsd 0011202

      CELL PARAMETERS:    3.4740   3.4740  11.2500   90.000   90.000  120.000
      SPACE GROUP: P6_3/mmc  
      X-RAY WAVELENGTH:     1.541838
      Cell Volume:    117.583
      Density (g/cm3):     13.725
      MAX. ABS. INTENSITY / VOLUME**2:      974.3777095    
      RIR:     23.116
      RIR based on corundum from Acta Crystallographica A38 (1982) 733-739
               2-THETA      INTENSITY    D-SPACING   H   K   L   Multiplicity
                29.69          7.90        3.0086    1   0   0         6
                30.76         43.12        2.9064    1   0   1        12
                31.82         34.98        2.8125    0   0   4         2
                33.79        100.00        2.6529    1   0   2        12
                38.36         23.15        2.3467    1   0   3        12
                44.08          5.05        2.0546    1   0   4        12
                50.66          9.65        1.8018    1   0   5        12
                52.70         22.54        1.7370    1   1   0         6
                57.96         18.28        1.5913    1   0   6        12
                62.27          4.74        1.4910    2   0   1        12
                62.89         24.41        1.4779    1   1   4        12
                64.08         12.85        1.4532    2   0   2        12
                65.89          3.88        1.4176    1   0   7        12
                66.49          3.34        1.4062    0   0   8         2
                67.03          3.65        1.3961    2   0   3        12
                76.12          2.36        1.2505    2   0   5        12
                82.15          5.54        1.1733    2   0   6        12
                83.80          1.74        1.1543    1   0   9        12
                85.91          1.08        1.1314    2   1   1        24
                87.52          3.08        1.1146    2   1   2        24
                89.17          1.46        1.0983    2   0   7        12
                89.71          7.68        1.0930    1   1   8        12
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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.