Research Data Leeds Repository

Citation

Dougan, Lorna and Lenton, Samuel and Rhys, Natasha and Towey, James and Soper, Alan (2017) Perchlorate neutron data. University of Leeds. [Dataset] https://doi.org/10.5518/210

Dataset description

Although there is no general consensus on the nature of water on Mars the discovery by the Phoenix Lander of calcium and magnesium perchlorates in Martian soil samples has fueled much speculation that flows of perchlorate brines might be the cause of the observed channeling and weathering in the surface. Magnesium perchlorate forms a eutectic mixture with water with a minimum freezing point around 206 K and this matches the observed ground temperatures, which, in summer at the equator, typically range between 195K and 280K. Here we study the structure of water in a mimetic of Martian water, namely magnesium perchlorate aqueous solution at its eutectic composition, using neutron diffraction in combination with hydrogen isotope labelling and empirical potential structure refinement. We find that the tetrahedral structure of water is heavily perturbed under these conditions, the effect being equivalent to pressurizing pure water to pressures of order 2 GPa or more. In addition, the Mg2+ and ClO4- ions appear charge-ordered, confining the water on length scales of order 9 Å, so preventing ice formation at low temperature. These effects may explain the low evaporation rates and high deliquescence of these salt solutions which are essential for stability within the low relative humidity environment of the Martian atmosphere.

Keywords:	Neutron, diffraction, water, structure
Subjects:	F000 - Physical sciences > F100 - Chemistry
Divisions:	Faculty of Engineering and Physical Sciences > School of Physics and Astronomy
Related resources:	Location Type https://doi.org/10.1038/s41467-017-01039-9 Publication https://eprints.whiterose.ac.uk/123374/ Publication
License:	Creative Commons Attribution 4.0 International (CC BY 4.0)
Date deposited:	05 Sep 2017 13:10
URI:	https://archive.researchdata.leeds.ac.uk/id/eprint/244
Additional details Additional details Creators or authors: Creators ORCID Other ID Email Primary affiliation Primary affiliation ID Primary affiliation ID type Secondary affiliation Secondary affiliation ID Secondary affiliation ID type Dougan, Lorna https://orcid.org/0000-0002-2620-5827 University of Leeds https://ror.org/024mrxd33 ror Lenton, Samuel https://orcid.org/0000-0003-1740-9980 University of Leeds https://ror.org/024mrxd33 ror University of York https://ror.org/04m01e293 ror Rhys, Natasha University of Leeds https://ror.org/024mrxd33 ror University of Oxford https://ror.org/052gg0110 ror Towey, James University of Leeds https://ror.org/024mrxd33 ror Soper, Alan https://orcid.org/0000-0002-7903-8356 University of Leeds https://ror.org/024mrxd33 ror ISIS Neutron and Muon Source https://ror.org/01t8fg661 ror Type of data: Dataset Research funders: EPSRC, ERC Grant numbers: EP/H020616/1, 258259 Publication date: 2017 Resource language: English Metadata language: English Research project title: Biophysics of cryopreservation, Extreme biophysics Publisher: University of Leeds Contact email: L.dougan@leeds.ac.uk Last Modified: 13 Aug 2024 07:54

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Documentation

Dataset description [1kB] Dataset description [1kB] Dataset description [1kB] Security: Anyone File name: README.txt Content type: Documentation Mime-Type: text/plain License: Creative Commons Attribution 4.0 International (CC BY 4.0) File size: 1kB

Data

Magnesium perchlorate at room temperature 298K [4MB] Magnesium perchlorate at room temperature 298K [4MB] Magnesium perchlorate at room temperature 298K [4MB] Security: Anyone File name: MgCl2O8_1577_298K.zip Content type: Data Description: Verbal frames chosen by study participants for summarising a climate projection; their climate change and environmental values, political affiliation and diverse demographic variables Mime-Type: application/zip License: Creative Commons Attribution 4.0 International (CC BY 4.0) File size: 4MB

Magnesium perchlorate at low temperature 216K [18MB] Magnesium perchlorate at low temperature 216K [18MB] Magnesium perchlorate at low temperature 216K [18MB] Security: Anyone File name: MgCl2O8_1577_216K.zip Content type: Data Description: Linear models and descriptive analysis for offers made by proposers and expectations of offers by responders Mime-Type: application/zip License: Creative Commons Attribution 4.0 International (CC BY 4.0) File size: 18MB