Urea
      Swaminathan S, Craven B M
      Acta Crystallographica B40 (1984) 300-306
      The crystal structure and molecular thermal motion of urea
      at 12, 60 and 123 K from neutron diffraction
      Note: neutron data, T = 123 K
      Locality: synthetic
      _database_code_amcsd 0020672

      CELL PARAMETERS:    5.5840   5.5840   4.6890   90.000   90.000   90.000
      SPACE GROUP: P-42_1m   
      X-RAY WAVELENGTH:     1.541838
      Cell Volume:    146.208
      Density (g/cm3):      1.364
      MAX. ABS. INTENSITY / VOLUME**2:      9.633665053    
      RIR:      2.300
      RIR based on corundum from Acta Crystallographica A38 (1982) 733-739
               2-THETA      INTENSITY    D-SPACING   H   K   L   Multiplicity
                22.52        100.00        3.9485    1   1   0         4
                24.79         22.14        3.5909    1   0   1         8
                29.58         27.68        3.0203    1   1   1         4
                32.06          6.58        2.7920    2   0   0         4
                35.96         14.28        2.4972    2   1   0         8
                37.49         11.69        2.3989    2   0   1         8
                38.39          1.53        2.3445    0   0   2         2
                40.95          4.44        2.2041    2   1   1         8
                41.79          5.89        2.1617    1   0   2         8
                44.97          1.84        2.0159    1   1   2         4
                45.97          5.45        1.9742    2   2   0         4
                50.14          6.16        1.8195    2   2   1         4
                52.93          2.63        1.7300    3   0   1         8
                53.62          1.52        1.7093    2   1   2         8
                55.62          6.96        1.6525    3   1   1         8
                61.39          1.01        1.5101    2   2   2         4
                61.62          1.42        1.5051    1   0   3         8
                70.37          1.51        1.3380    4   0   1         8
                71.16          1.89        1.3249    2   1   3         8
                71.71          1.92        1.3162    3   3   0         4
                76.26          1.26        1.2486    4   2   0         8
                82.40          1.42        1.1704    3   1   3         8
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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.