Alicewilsonite-(YCe) mineral

A sodium-strontium-yttrium-cerium carbonate mineral approved as IMA 2020-055, with ideal IMA-CNMNC September 2026 formula Na2Sr2YCe(CO3)6(H2O)3. The YCe suffix reflects dominance at different crystallographic sites, not a ranking of bulk rare-earth concentrations. This species is distinct from donnayite-(Y), alicewilsonite-(YLa), individual elements and mixed ores. Lykova et al. (2023, Part 2) characterized holotype CMNMC 53660 from Mont Saint-Hilaire, Canada, previously labelled donnayite-(Y). The zoned crystal contains an outer alicewilsonite-(YCe) rim and an inner donnayite-(Y)/gaidonnayite assemblage; the single-crystal diffraction grain was selected from the alicewilsonite rim. Wavelength-dispersive electron-microprobe measurements used 20 kV, 10 nA, grain-dependent 20–50 micrometre beams and corrections for beam instability. Table 1 reports holotype means of 8.52 wt% Y2O3 and 9.52 wt% Ce2O3 from six analyses. CO2 and H2O were calculated because insufficient pure material could be isolated; infrared spectra support water qualitatively. The 293 K single-crystal refinement gives triclinic P1 and R1 = 0.055 with an 87:13 twin model. Crystal quality limits structural detail: hydrogen was not reliably located, Ca was omitted from the model, and Ce and Dy represented lighter and heavier lanthanides as scattering proxies. Main-text Sr1 site composition uses Ce0.23 whereas Table 4 and the official CIF use Ce0.22; Table 3's Rint of 0.062 also differs from the CIF agreement field of 0.0394. These unresolved differences prevent unqualified reuse of detailed model occupancies or agreement statistics. Natural intergrowths and proposed replacement relations are geological interpretations, not controlled conversion experiments. Qualitative room-temperature dissolution with effervescence in aqueous HCl lacks specified concentration, time and yield, and is not curated as an extraction or recovery mechanism. No microbial process, industrial deployment or transferred elemental criticality is established by this characterization.

Record source: data/records/alicewilsonite-yce.yaml