ISIS Neutron and Muon Source Data Journal

First and Second Order Phase Transitions in Glyphosate at High Pressure

Abstract: A recent high pressure Raman study indicates that glyphosate undergoes two phase transitions at ~1 GPa and between ~4 GPa. Single crystal X-ray diffraction finds no discontinuities in the lattice or structural parameters. These contradictory findings were resolved by partitioning the cell volume into contributions from occupied and void space to reveal two small events at 0.9 and 3.8 GPa in the occupied volume, suggesting that the transitions are second order and correspond to changes in the mechanism by which pressure is accommodated. This neutron time will resolve an unusual oscillation in the position of one H-atom, required for the packing energy calculations that partly define the order of the transition. Glyphosate becomes polycrystalline at ~6 GPa after a first order phase transition; we will also collect data for complete structural characterisation of this new phase.

Principal Investigator: Professor Simon Parsons
Local Contact: Dr Nicholas Funnell
Experimenter: Mr Cameron Wilson
Experimenter: Dr Peter Wood

DOI: 10.5286/ISIS.E.RB2220264

ISIS Experiment Number: RB2220264

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 Simon Parsons et al; (2023): First and Second Order Phase Transitions in Glyphosate at High Pressure, STFC ISIS Neutron and Muon Source, https://doi.org/10.5286/ISIS.E.RB2220264

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