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CMMMech > Mineral > Bijvoetite-(Y)

Bijvoetite-(Y) mineral

Hydrated yttrium-uranyl hydroxy-carbonate mineral with current September 2026 IMA-CNMNC approved formula Y8(UO2)16O8(CO3)16(OH)8(H2O)25·14H2O, status Rn (renamed), and special-procedure tag 1987 s.p. (originally described as bijvoetite in 1982 under IMA 1981-035 and suffixed in 1987; listed under 1987 s.p. in the IMA Master List rather than a numbered CURIE). Deliens and Piret (1982) described the holotype specimen (Royal Museum for Central Africa RGM 13.781) from the lower oxidation zone of the Shinkolobwe uranium deposit, Shaba (Katanga), Democratic Republic of the Congo, associated with lepersonnite-(Gd), sklodowskite, curite, uranophane, becquerelite, rutherfordine, and studtite. Original electron-microprobe and gas-chromatographic CO2 analysis (Table 2, p. 235) yielded UO3 60.66, Y2O3 7.52, Dy2O3 5.61, Gd2O3 2.80, Tb2O3 0.96, CO2 8.88, H2O 13.57 (by difference), total 100.00 wt%, initially interpreted on an orthorhombic C2ma/Cm2b/Cmma cell with formula (RE)2O3·4UO3·4CO2·~14H2O. Li, Burns, and Gault (2000) re-analyzed the holotype by WDS (mean of 3 points, Table 2, p. 155: Y2O3 5.81, Ce2O3 0.33, Nd2O3 2.13, Sm2O3 1.73, Eu2O3 0.46, Gd2O3 1.78, Tb2O3 0.26, Dy2O3 2.15, Er2O3 0.62, CaO 0.19, UO3 67.30, CO2 9.51 calc, H2O 9.49 calc, total 101.76 wt%) and solved the structure by CCD single-crystal X-ray diffraction on a rotationally twinned crystal in non-standard monoclinic space group B1211 (a = 21.234(3), b = 12.958(2), c = 44.911(6) A, beta = 90.00(2) degrees, V = 12357(3) A3 in Table 1 / 12357(6) A3 in abstract, Z = 4, R = 8.37% in Table 1 / 8.4% in abstract, wR = 6.99%, S = 0.814 for 6622 observed reflections with |Fo| >= 4sigma(|Fo|)), establishing [(UO2)16O8(OH)8(CO3)16]16- chains linked directly by [REO8]/[REO9] polyhedra into mixed uranyl-REE carbonate sheets with interlayer H2O. Distinct from kamotoite-(Y), shabaite-(Nd), astrocyanite-(Ce), and elemental yttrium or uranium; no criticality designation, microbial mechanism, or industrial recovery yield is asserted.

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Sources & References

  1. ima_2026_09: IMA-CNMNC, The New IMA List of Minerals, September 2026, PDF page 26, Bijvoetite-(Y) row: formula Y8(UO2)16O8(CO3)16(OH)8(H2O)25·14H2O, status Rn, IMA No. 1987 s.p., country DR Congo, first reference Canadian Mineralogist 20 (1982), 231, second reference Canadian Mineralogist 38 (2000), 153; column definitions on PDF page 1.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-22)
  2. deliens_1982_bijvoetite: Deliens M, Piret P (1982), Bijvoetite et lepersonnite, carbonates hydrates d'uranyle et de terres rares de Shinkolobwe, Zaire, Canadian Mineralogist 20:231-238. Complete 8-page primary PDF visually inspected: Shinkolobwe holotype RGM 13.781 occurrence, optical/crystallographic properties, powder XRD Table 1, and EMPA/GC chemical analysis Table 2 pp. 231-236.
    https://www.rruff.net/doclib/cm/vol20/CM20_231.pdf (accessed 2026-10-22)
  3. li_2000_bijvoetite: Li Y, Burns PC, Gault RA (2000), A new rare-earth-element uranyl carbonate sheet in the structure of bijvoetite-(Y), Canadian Mineralogist 38:153-162, DOI 10.2113/gscanmin.38.1.153. Complete 10-page primary PDF visually inspected: WDS chemical re-analysis Table 2 and monoclinic B1211 single-crystal structure refinement on twinned holotype crystal Tables 1, 3-5 and Figures 1-4 pp. 153-161.
    https://www.rruff.net/doclib/cm/vol38/CM38_153.pdf (accessed 2026-10-22)

Curation History

Timestamp Curator Action Summary
2026-10-22T07:20:00Z antigravity CREATE Created bijvoetite-(Y) mineral record from the September 2026 IMA master list (1987 s.p., status Rn), complete 1982 Shinkolobwe holotype description, and complete 2000 monoclinic B1211 crystal-structure determination.

Record source: data/records/bijvoetite-y.yaml