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Phosphoferrite mineral

Phosphoferrite is the ferrous phosphate mineral with ideal formula Fe2+3(PO4)2(H2O)3. The September 2026 IMA list records redefined status under the 1980 special procedure. It is distinct from the more hydrated species vivianite and ludlamite, the Mn-dominant related mineral reddingite, and ferric kryzhanovskite. The historical Hagendorf Sud specimen studied by Moore (1971) contained Mn and Ca and was not a pure synthetic Fe endmember. Laboratory heating produced a source-reported ferric crystalline product with diffraction similarities to the starting material. Later structural work by Moore, Araki and Kampf (1980) corrected substantial indexing and unit-cell errors in the earlier natural kryzhanovskite comparison; this record therefore retains the limited heating observation without treating the earlier cell dimensions, exact structural model or pure-product identity as established. These are abiotic laboratory observations, not microbial extraction or demonstrated industrial recovery. No criticality designation is inherited from iron or phosphorus.

Microbial & Biochemical Mechanisms (1)

Abiotic heating-associated oxidation of natural phosphoferrite

redox transformation

Moore (1971) reports that Hagendorf Sud phosphoferrite heated in air at 240 degrees C for five days oxidized to a ferric equivalent while retaining single-crystal and powder diffraction features interpreted as isotypic with the initial material, with broadened lines and spots. This establishes a qualified thermal oxidation observation for the investigated natural specimen. It does not establish a mass-balanced yield of pure kryzhanovskite, a measured hydrogen-production pathway or a microbial process. The proposed internal proton-cleavage mechanism was a hypothesis; the author specifically proposed anaerobic heating and quantitative hydrogen collection as a future test.

Experimental Context & Analytical Limits:
Natural phosphoferrite crystals from Hagendorf Sud, supplied by D. J. Fisher; Table 1 uses a historical chemical analysis with Mn and Ca substitution. Crystals of phosphoferrite, vivianite and ludlamite were heated separately in open capillaries at 120, 180 and 240 degrees C for five days, with a chromel-alumel thermocouple in contact with the crystals. Products were quenched to room temperature, dissolved in cold HCl and titrated against potassium dichromate; diffraction was compared with starting material. The explicit phosphoferrite outcome is reported at 240 degrees C; lower-temperature phosphoferrite outcomes, sample masses, replicate counts, quantitative conversion uncertainty and a mass balance are not supplied in this experiment description. Vivianite and ludlamite are different-mineral comparisons, not matched oxygen-free phosphoferrite controls. The 1980 study revises the earlier natural kryzhanovskite reference data, not this heating experiment, and does not independently replicate its outcome.
Curated Evidence Points:
Page 14 Oxidation Sequences gives the capillary temperatures, five-day duration, air atmosphere, thermocouple, HCl/dichromate analysis and qualified ferric/isotypic outcome. Table 1 page 2 and Figure 7 page 15 distinguish initial P-1, heated P-1-prime and the separate natural K-1 specimen. Page 16 presents hydrogen release as a proposed mechanism requiring an anaerobic collection test, not a measured product.
Page 790 and Tables I-II explicitly revise earlier natural kryzhanovskite cell parameters and 14 of 31 indexed powder lines; its c-axis differs by 4.2 percent from the earlier result. Page 792 retains historical chemical analyses because little type material was available. These corrections limit exact structural and compositional inference from Moore (1971), while the 1980 work does not report a repeat of the phosphoferrite heating experiment. Its synthetic-endmember comparison draws on Moore and Araki (1976), not a new synthesis in 1980.

Sources & References

  1. ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. Phosphoferrite row, PDF page 171: Fe2+3(PO4)2(H2O)3, Rd, 1980 s.p.; status definitions page 1.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-15)
  2. moore1971: Moore PB (1971). The Fe2+3(H2O)n(PO4)2 homologous series: crystal-chemical relationships and oxidized equivalents. American Mineralogist 56:1-17. Complete original. Table 1 page 2; Oxidation Sequences page 14; Figure 7 page 15; proposed mechanism and proposed future hydrogen test page 16.
    https://www.rruff.net/doclib/am/vol56/AM56_1.pdf (accessed 2026-10-15)
  3. moore1980: Moore PB, Araki T, Kampf AR (1980). Nomenclature of the phosphoferrite structure type: refinements of landesite and kryzhanovskite. Mineralogical Magazine 43:789-795. Complete seven-page original; revised cell/indexing comparison page 790/Table I, powder data page 791/Table II, chemical-source limits page 792/Table III, nomenclature page 795. Publication is June 1980; Cambridge online posting in 2018 is not a new experiment.
    https://doi.org/10.1180/minmag.1980.043.330.14 (accessed 2026-10-15)

Curation History

Timestamp Curator Action Summary
2026-10-15T15:12:16.332826Z codex (GPT-6; codex) CREATE Created phosphoferrite with dated mineral nomenclature and qualified abiotic heating evidence, preserving mixed natural composition, later indexing corrections and the untested hydrogen pathway.

Record source: data/records/phosphoferrite.yaml