{
  "abstract": "The vibrational signature (Raman and IR) of natural ludlamite single crystals is discussed, along with the evolution of the Raman spectrum after heating to 90, 150, and 200 • C. The observation of broad \"ABC\" bands in the stretching mode region-characteristic of a strong, symmetric hydrogen bond-indicates the formation of H 2 O-H + -OH 2 (or H 5 O 2 + ) species. After deuteration, the νOH/νOD wavenumber ratios show values between 1.18 and 1.25, confirming the strong bonding that leads to an (H₅O₂⁺, 2 H₂O) n water layer between the [Fe 3 (PO 4 ) 2 ] n sheets, as well as the high proton mobility. Consequently, the chemical formula of the compound should rather be Fe 2.5 (PO 4 ) 2 H 5 O 2 ⋅2⋅H 2 O. An Fe 3 III O(HPO₄) 2 ⋅nH₂O form is obtained by immersion in molten ammonium nitrate.\n\nLudlamite, like its lamellar counterparts HUP, HUAS, and HFeS, is a reasonably good proton conductor with a thermal stability up to ≈ 150 • C.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 3,
  "authors": [
    {
      "name": "Philippe Colomban"
    },
    {
      "name": "Ricardo Scholz"
    },
    {
      "name": "Roberto L Moreira"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/9e68s94gsweeq.bib",
  "cited_by": 0,
  "doi": "10.1016/j.molstruc.2026.147932",
  "fulltext_url": null,
  "id": "9e68s94gsweeq",
  "issns": [
    "0022-2860",
    "0022-2860"
  ],
  "landing_url": "https://hal.science/hal-05844230v1",
  "language": "en",
  "licence": "CC-BY-NC-4.0",
  "licence_label": "CC BY-NC 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "hal",
      "0.chim"
    ],
    [
      "hal",
      "0.phys"
    ],
    [
      "openalex",
      "2505|Solid-state spectroscopy and crystallography"
    ]
  ],
  "openalex": "W7223570475",
  "pdf_url": "https://hal.science/hal-05844230/document",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-30",
  "publisher": "Elsevier",
  "ris": "https://research.draconitic.com/paper/9e68s94gsweeq.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:03Z",
      "native_id": "hal-05844230",
      "source": "hal",
      "url": "https://hal.science/hal-05844230v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:2505|Solid-state spectroscopy and crystallography",
      "subfield": "materials-polymers"
    }
  ],
  "title": "Protonated water layer in Ludlamite lamellar iron phosphate (Fe3(PO4)2·4H2O)",
  "title_text": "Protonated water layer in Ludlamite lamellar iron phosphate (Fe3(PO4)2·4H2O)",
  "type": "peer-reviewed",
  "updated_at": "2026-10-31T12:20:56Z",
  "url": "https://research.draconitic.com/paper/9e68s94gsweeq",
  "venue": "Journal of Molecular Structure",
  "versions": []
}