NpO2
      Wyckoff R W G
      Crystal Structures 1 (1963) 239-444
      Second edition. Interscience Publishers, New York, New York
      Fluorite structure
      _database_code_amcsd 0011703

      CELL PARAMETERS:    5.4341   5.4341   5.4341   90.000   90.000   90.000
      SPACE GROUP: Fm3m      
      X-RAY WAVELENGTH:     1.541838
      Cell Volume:    160.466
      Density (g/cm3):     11.133
      MAX. ABS. INTENSITY / VOLUME**2:      932.3968103    
      RIR:     27.270
      RIR based on corundum from Acta Crystallographica A38 (1982) 733-739
               2-THETA      INTENSITY    D-SPACING   H   K   L   Multiplicity
                28.45        100.00        3.1374    1   1   1         8
                32.97         36.35        2.7171    2   0   0         6
                47.31         43.85        1.9212    2   2   0        12
                56.14         38.66        1.6384    3   1   1        24
                58.87          8.48        1.5687    2   2   2         8
                69.15          5.76        1.3585    4   0   0         6
                76.40         13.32        1.2467    3   3   1        24
                78.76          9.70        1.2151    4   2   0        24
                88.05         10.47        1.1092    4   2   2        24
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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.