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Vandenbrandeite mineral

Vandenbrandeite is the copper uranyl tetrahydroxide mineral Cu(UO2)(OH)4, distinct from elemental uranium, copper commodities and other copper uranyl minerals. The September 2026 IMA list gives grandfathered status G; 1932 is its original-description year, not an approval accession. Colmenero and colleagues refined a natural Musonoi, Democratic Republic of Congo crystal in triclinic P-1 at room temperature, including hydrogen positions obtained from difference-Fourier maps with soft O-H constraints. Their experimental structure and Raman spectrum are distinct from calculated elastic and thermodynamic properties. The natural Kalongwe material used for the earlier thermal study is a separate specimen population. No criticality designation, microbial mechanism or industrial recovery is inferred.

Microbial & Biochemical Mechanisms (1)

Abiotic thermal dehydroxylation of natural vandenbrandeite

other

Furnace heating of selected natural crystals produced progressive hydroxyl loss, fissuring and poorly crystalline intermediate material, followed by copper uranium oxide products at higher temperatures. The authors reported CuUO4 diffraction lines at 900 degrees C together with weaker CuU3O10 and U3O8 reflections. This is laboratory thermal alteration of a mineral, not a demonstrated uranium separation or isolated pure-product recovery.

Experimental Context & Analytical Limits:
The Kalongwe specimen from the then Shaba province of Zaire contained kasolite veinlets and inclusions. After water/acetone washing and stirring, small crystals were selected to reduce inclusions; EDAX still reported traces of Pb and Si. Heating was in air in a programmed furnace, with the stated treatment range 300-950 degrees C. Heated and unheated material was compared by IR, ESR, SEM/EDAX and powder XRD. Heating rate, dwell times, mass loading and replicate counts were not specified. The initial 21.00% Cu and 79.00% U values are metal-normalized EDAX proportions, not whole-mineral mass fractions or ore grades.
Curated Evidence Points:
Figure 4 compares original, 300, 600 and 950 degrees C infrared spectra with uranium oxide reference spectra. Figure 6 shows fissures in the 300 degrees C sample and subsequent morphological changes at 500, 700 and 950 degrees C. Page 181 reports poorly resolved diffraction at 600 degrees C, unsuccessful crystallization in the 500-700 degrees C interval, and CuUO4 with weaker CuU3O10 and U3O8 diffraction at 900 degrees C. These product assignments are author-reported; the underlying powder patterns are not plotted in this article.
Pages 180-181 infer a topochemically directed process from spectroscopy, morphology and relatively homogeneous Cu/U distribution. This does not directly resolve an atomic reaction pathway or establish a pure product. Thermal characterization is incomplete: the abstract describes material as practically X-ray amorphous up to about 700 degrees C, while page 180 says about 600 degrees C. Page 180 reports 9.04% mass loss at 250-380 degrees C, outside the stated lower furnace-treatment bound, without a corresponding raw TG curve or detailed measurement method for that value. It is not adopted as a calibrated onset, replicated yield or new quantitative observation.
Context_only Source: colmenero2019
Room-temperature natural-crystal diffraction supports identity. The predicted temperature-dependent stability and peroxide reaction constants in this separate computational study do not experimentally validate the 2002 heating pathway or demonstrate performance in a spent-fuel repository. The calculated and experimental structures also use different axis settings as explicitly described on page 40713.

Sources & References

  1. ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. Vandenbrandeite row, PDF page 226; status and year definitions page 1. Fresh official PDF and row inspected.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-16)
  2. colmenero2019: Colmenero F, Plasil J, Cobos J, Sejkora J, Timon V, Cejka J, Fernandez AM, Petricek V (2019). Structural, mechanical, spectroscopic and thermodynamic characterization of the copper-uranyl tetrahydroxide mineral vandenbrandeite. RSC Advances 9:40708-40726. DOI 10.1039/C9RA09047A. Complete published 19-page PDF and Europe PMC XML acquired; experimental methods page 40711, structural discussion and Table 1 pages 40712-40714 inspected. Supplementary CIFs and tables were not acquired; no deposited structure was re-refined.
    https://doi.org/10.1039/C9RA09047A (accessed 2026-10-16)
  3. botto2002: Botto IL, Barone VL, Sanchez MA (2002). Spectroscopic and thermal contribution to the structural characterization of vandenbrandeite. Journal of Materials Science 37:177-183. DOI 10.1023/A:1013182917829. Complete published seven-page article acquired from the University of La Plata repository. Specimen preparation and furnace methods pages 177-178; thermal results pages 180-181; original Figures 4-6 pages 181-183 inspected. This paper refers to earlier TG/DTA data; those earlier raw curves were not independently acquired.
    https://doi.org/10.1023/A:1013182917829 (accessed 2026-10-16)

Curation History

Timestamp Curator Action Summary
2026-10-16T06:50:17Z codex (GPT-6; codex) CREATE Added verified vandenbrandeite identity and bounded natural-mineral thermal transformation with source limitations.

Record source: data/records/vandenbrandeite.yaml