{
  "abstract": "Cranswickite, the rarer of the two natural polymorphs of MgSO4·4H2O, has until now been known only from its type locality and characterized solely by X-ray powder methods, leaving its hydrogen-atom positions undetermined. The crystal structure of perdeuterated cranswickite, MgSO4·4D2O, prepared by controlled-humidity dehydration of the heptahydrate, has been refined by Rietveld analysis of time-of-flight neutron powder diffraction data at 10 K and 295 K, with all deuteron positions and displacement parameters refined without restraints, yielding the first complete hydrogen-bond geometry for this phase. Variable-temperature measurements (10–340 K) reveal strongly anisotropic thermal expansion: one principal axis of the expansion tensor is negative over the entire temperature range, reaching α1 = −3.7(3) × 10-5 K-1 at 335 K, which is balanced by positive expansion of similar magnitude within the ac plane, such that the principal expansivities [α1:α2:α3 = −1.04(4):2.90(4):1.00(5) at 295 K] yield zero area expansion of the ac plane. At 330 K cranswickite’s transformation to starkeyite accompanied by a volume reduction of 4.72% was observed, which is among the largest known density increases associated with a phase transition. The relevance of these findings to MgSO4 hydrates as candidate rock-forming minerals on Mars and the icy Galilean satellites is discussed.",
  "abstract_shown": true,
  "affiliations": [
    "Tremough Campus",
    "University of Exeter",
    "Harwell Science and Innovation Campus, Fermi Avenue, Didcot, UK, OX11 0DE",
    "ISIS Neutron and Muon Source",
    "STFC Rutherford Appleton Laboratory, Harwell Science and Innovation Campus"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 5,
  "authors": [
    {
      "affs": [
        0,
        1,
        2,
        3,
        4
      ],
      "name": "Johannes M. Meusburger",
      "orcid": "0000-0003-4367-3566"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Karen A. Hudson-Edwards"
    },
    {
      "affs": [
        2
      ],
      "name": "Eamonn T. Connolly"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Rich A. Crane"
    },
    {
      "affs": [
        3,
        4
      ],
      "name": "A. Dominic Fortes"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/2hgs4ygs50bd0.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15011185/v1",
  "fulltext_url": null,
  "id": "2hgs4ygs50bd0",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15011185/v1",
  "language": null,
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "1908|High-pressure geophysics and materials"
    ]
  ],
  "openalex": "W7223907137",
  "pdf_url": null,
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-28",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/2hgs4ygs50bd0.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:26Z",
      "native_id": "10.26434/chemrxiv.15011185",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15011185/v1"
    }
  ],
  "subjects": [
    {
      "field": "earth",
      "origin": "openalex:1908|High-pressure geophysics and materials",
      "subfield": "geophysics"
    }
  ],
  "title": "Hydrogen bonding, thermal expansion, and phase transition of cranswickite (MgSO4 · 4H2O)",
  "title_text": "Hydrogen bonding, thermal expansion, and phase transition of cranswickite (MgSO4 · 4H2O)",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:26Z",
  "url": "https://research.draconitic.com/paper/2hgs4ygs50bd0",
  "venue": "ChemRxiv",
  "versions": []
}