Cerianite-(Ce) mineral
Cerianite-(Ce) is the cubic cerium dioxide mineral, with ideal formula CeO2. The IMA-CNMNC September 2026 list records renamed status Rn and the 1987 special-procedure action, not a sequential approval number. Natural material can contain thorium; this does not establish thorium in the experimental synthetic analogue. The accepted experiment produces a minor CeO2 phase by heating a fungal-conditioned phosphate/oxalate precursor, not by direct living-cell precipitation of cerianite. Elemental cerium criticality is not inherited by this mineral.
Microbial & Biochemical Mechanisms (1)
Abiotic thermal production of cerianite from a fungal-conditioned precursor
other
A washed, dried phosphate/oxalate precipitate prepared using biomass-free Aspergillus niger ATCC 1015 struvite leachate and synthetic CeCl3 was heated to 1000°C. XRD of the higher-Ce-loading product was assigned to a mixture of CePO4 and CeO2, termed cerianite by the authors. The microbial flag is false for this thermal conversion itself; fungal culture produced the upstream leachate. This is the thermal stage of the same Kang 2022 experiment already cited under cerium, phosphorus and struvite, not an independent replication.
Experimental Context & Analytical Limits:
Laboratory upstream culture used 1% w/v pulverized struvite/dittmarite feed from Veolia's Exeter operating site, oven-treated at 105°C for 48 h, in modified Czapek-Dox medium containing 1 g/L Na2HPO4; initial pH 5.5, 1 × 10^6 spores/mL, 200 mL in 500 mL flasks, 14 days at 25°C and 125 rpm in darkness. Biomass was removed by filtration. The filtrate received 0.5 g H-form AG 50W-X8 resin per 5 mL for 24 h, was adjusted to pH 7.5 with 4 M NaOH and filtered at 0.25 micrometres. Ten-mL CeCl3 reactions at 20 or 50 mM final Ce loading ran for 24 h at room temperature on a roller mixer; treatments were triplicate. Solids were centrifuged at 2553 g for 30 min, washed three times and dried at room temperature for at least two weeks. Thermal analysis used less than 100 mg in a NETZSCH STA 409PC with SiC furnace, heated at 10 K/min to 1000°C under dry N2 at 100 cm3/min and held until constant weight. This is a laboratory thermal conversion, not fungal growth at high temperature, demonstrated industrial recovery, or treatment of a real Ce waste stream.
Laboratory upstream culture used 1% w/v pulverized struvite/dittmarite feed from Veolia's Exeter operating site, oven-treated at 105°C for 48 h, in modified Czapek-Dox medium containing 1 g/L Na2HPO4; initial pH 5.5, 1 × 10^6 spores/mL, 200 mL in 500 mL flasks, 14 days at 25°C and 125 rpm in darkness. Biomass was removed by filtration. The filtrate received 0.5 g H-form AG 50W-X8 resin per 5 mL for 24 h, was adjusted to pH 7.5 with 4 M NaOH and filtered at 0.25 micrometres. Ten-mL CeCl3 reactions at 20 or 50 mM final Ce loading ran for 24 h at room temperature on a roller mixer; treatments were triplicate. Solids were centrifuged at 2553 g for 30 min, washed three times and dried at room temperature for at least two weeks. Thermal analysis used less than 100 mg in a NETZSCH STA 409PC with SiC furnace, heated at 10 K/min to 1000°C under dry N2 at 100 cm3/min and held until constant weight. This is a laboratory thermal conversion, not fungal growth at high temperature, demonstrated industrial recovery, or treatment of a real Ce waste stream.
Curated Evidence Points:
Support
Source:
kang_2022
Figure 7b is the heated product from the 50 mM Ce precursor; reference traces 7c and 7d are CePO4 and CeO2 respectively. Table 2 reports Rietveld-fitted proportions of 90.4% CePO4 and 9.6% CeO2. These are modelled phase proportions in the mixed solid, not a cerium recovery percentage, isolated cerianite yield or independently established absolute purity. Duplicate XRD samples were scanned over 3–60° 2-theta with Cu K-alpha radiation. Typical patterns and fitted values are shown from several determinations, without reported fit uncertainties.
Support
Source:
kang_2022
The 20 mM precursor gives a contrasting outcome: Table 2 reports CeO2 undetected after heating and 100% fitted CePO4, with product trace Figure 7a. Before heating, Figure 6 and Table 2 assign the 50 mM precursor to 78.3% CePO4.H2O and 21.7% Ce2(C2O4)3.10H2O; oxalate was undetected in the 20 mM precursor. Undetected does not establish literal absence below an unspecified phase-detection limit.
Partial
Source:
kang_2022
Figure 8 shows distinct thermal mass-loss profiles and the Discussion attributes the higher-loading CeO2 to oxalate decomposition. No time-resolved diffraction or direct oxidation-state assay establishes the complete reaction pathway. The stated purge gas is nitrogen, so air oxidation is not assumed. Upstream solution-Ce removal above 99% and precursor precipitate mass in Figure 3 are not cerianite recovery measurements. No matched synthetic phosphate/oxalate or untreated-filtrate comparator is reported for the Ce precipitation and thermal sequence; microbial necessity is not established.
Partial
Source:
kang_2022
Discussion also mentions Na3Ce(PO4)2 attributed to Na-containing impurities, although Table 2 and Figure 7's reference legend account for CePO4 and CeO2 only. That additional phase is not quantified here and the fitted two-phase proportions are not an exhaustive composition claim. The Results points to Figure 7c/d while discussing specimens, but the caption identifies those as standards; specimen assignments here follow 7a/b and Table 2. The source's broad description of amorphous precursors does not erase their reported XRD phase fits.
Sources & References
-
ima_202609: IMA-CNMNC master list, September 2026: definitions pp. 1–2 and Cerianite-(Ce) row p. 39, CeO2, Rn, 1987 s.p.
https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-14) -
handbook_cerianite: Handbook of Mineralogy: Cerianite-(Ce), p. 105; natural composition, cubic structure and synthetic powder pattern
https://www.handbookofmineralogy.org/pdfs/cerianite-Ce.pdf (accessed 2026-10-14) -
kang_2022: Kang, Csetenyi, Gao and Gadd (2022). Solubilization of struvite and biorecovery of cerium by Aspergillus niger. Applied Microbiology and Biotechnology 106:821–833. Complete 13-page article; Methods pp. 823–824, Figures 1–9, Tables 1–2 and Discussion. DOI 10.1007/s00253-021-11721-0.
https://doi.org/10.1007/s00253-021-11721-0 (accessed 2026-10-14)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-14T20:48:35.684565+00:00 |
codex (GPT-6; codex) | CREATE | Created distinct cerianite mineral owner for the abiotic thermal stage of a verified fungal-conditioned precursor experiment, retaining mixed-phase fits and source inconsistencies. |
Record source: data/records/cerianite-ce.yaml