DL-NORLEUCINE - REDETERMINATION OF STRUCTURE AND OBSERVATIONS WITH SYNCHROTRON-RADIATION LAUE DIFFRACTION ON HEATING TOWARDS TRANSFORMATION

Redetermination of the structure of DL-norleucine (2-aminohexanoic aci d), C6H13NO2, has given more accurate geometrical information than the early work of Mathieson [Acta Cryst. (1953), 6, 399-403]. Synchrotron radiation Laue diffraction patterns recorded over a range of temperat ures have shown (a) the presence of streaks, indicating disorder in th e stacking of layers within the crystal at room temperature, (b) compl ete or almost complete disappearance of these streaks when the crystal is heated to ca 373 K, indicating annealing of the crystal, and (c) l oss of single crystal characteristics above 390 K so that it was not p ossible to record diffraction data for the high-temperature form propo sed by Mathieson.