ISIS Neutron and Muon Source Data Journal

Structures and thermal expansivity of recovered phases of urea II & III

Abstract: Urea is a prototypical hydrogen-bonded small molecule that has stimulated considerable fundamental research into its structure, elastic properties and polymorphism. Amongst the high-pressure phases, the structure of urea II is unknown. Our DFT calculations on urea III reveal an uncommon elastic property, which is negative linear compressibility (i.e., one direction in the crystal expands when the crystal as a whole is compressed). This has recently been observed experimentally. We propose to use new STFC funded apparatus to form urea II and urea III and then recover them to room pressure under liquid nitrogen. This allows us to obtain the highest-resolution neutron powder diffraction data, which will enable structure solution of urea II and high-precision thermal expansion measurements of both polymorphs. We will correlate the thermal expansion with H-bonding and high-P compressibility.

Principal Investigator: Professor Ian Wood
Experimenter: Dr Christopher Howard
Experimenter: Dr Weiwei Wang
Experimenter: Dr Dominic Fortes

DOI: 10.5286/ISIS.E.RB1710216

ISIS Experiment Number: RB1710216

Publisher: STFC ISIS Neutron and Muon Source

Data format: RAW/Nexus
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Data Citation

The recommended format for citing this dataset in a research publication is as:
[author], [date], [title], [publisher], [doi]

For Example:
Professor Ian Wood et al; (2017): Structures and thermal expansivity of recovered phases of urea II & III, STFC ISIS Neutron and Muon Source, https://doi.org/10.5286/ISIS.E.RB1710216

Data is released under the CC-BY-4.0 license.