Abstract
In this study a combination of neutron diffraction measurements and empirical potential structure refinement (EPSR) was used to investigate the time-averaged structure of a 0.30 mol fraction solution of urea in water at both 25 and 35 °C. These two temperatures were chosen in order to compare the structure of an undersaturated solution at 35 °C with that of a supersaturated solution at 25 °C. The results indicate that in moving into the supersaturated state the solutions show a significant and unexpected change in the self-aggregation of urea molecules. Urea-urea interactions present in the undersaturated solution become suppressed in the supersaturated region, in favor of interactions between urea and water so that overall the urea becomes more hydrated. Such a change may be viewed as a response of the system to the imposed supersaturation and a factor playing an important role in the observed metastability of the solutions.
Original language | English |
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Pages (from-to) | 1559-1565 |
Number of pages | 7 |
Journal | Crystal Growth and Design |
Volume | 8 |
Issue number | 5 |
Early online date | 16 Apr 2008 |
DOIs | |
Publication status | Published - 1 May 2008 |
Externally published | Yes |