Bainbridgeite-(NdCe) mineral

Anhydrous-layer-free hydrated sodium-barium-rare-earth carbonate mineral of the mckelveyite group with current September 2026 IMA-CNMNC approved formula Na2Ba2NdCe(CO3)6(H2O)3 and approval number IMA 2023-018. Lykova et al. (2026) characterized the holotype specimen (CMNMC 90534, where bainbridgeite-(NdCe) forms 20-30 um outer rims on barrel-shaped crystals over a bainbridgeite-(YCe) core CMNMC 46324 and an intermediate bainbridgeite-(YCe)-alicewilsonite-(YCe) zone in a carbonate pegmatite) and a second hornfels occurrence (CMNMC 52468, tabular crystals up to 0.5 mm) from the Poudrette (Demix) quarry, Mont Saint-Hilaire, Rouville County, Quebec, Canada. Wavelength-dispersive electron-microprobe analysis on holotype CMNMC 90534 (7 analyses, Table 1, p. 422) yielded Na2O 6.85, CaO 1.16, SrO 4.83, BaO 24.02, Y2O3 1.84, La2O3 6.07, Ce2O3 8.82, Pr2O3 0.76, Nd2O3 6.24, Sm2O3 3.34, Eu2O3 0.46, Gd2O3 2.74, Tb2O3 0.21, Dy2O3 0.53, ThO2 0.24, CO2* 27.33, H2O* 5.73, total 101.17 wt%, corresponding to the empirical formula Na2.09Ca0.19Sr0.44Ba1.48Y0.15La0.35Ce0.51Pr0.04Nd0.35Sm0.18Eu0.03Gd0.14Tb0.01Dy0.03Th0.01(CO3)5.86(H2O)3.00 (with CO2 and H2O calculated from stoichiometry and structure rather than directly assayed). Single-crystal X-ray diffraction at 293 K refined in triclinic space group P1 (a = 9.0525(3), b = 9.1178(2), c = 6.85180(19) A, alpha = 102.575(3), beta = 116.272(4), gamma = 59.788(4) degrees, V = 438.23(3) A3, Z = 1, R1 = 0.036, wR2 = 0.099 for 4140 independent reflections with I > 2sigma(I)) established a weloganite-type structure with six independent large cation sites (Ba1, Ba2, Ce3, Na4, Na5, Nd6), where light lanthanoids (Ce, La, Pr) partition into the larger 10-coordinated Ce3 polyhedron (Ce0.75Ba0.15Sr0.10) while Nd, heavier lanthanoids (Sm, Gd), and Y partition into the smaller 9-coordinated Nd6 polyhedron (Nd0.37Y0.33Na0.17Gd0.13; the refined Y occupancy exceeds the 0.15 apfu WDS rim average because the diffraction crystal included both the bainbridgeite-(NdCe) rim and bainbridgeite-(YCe) core). This intra-crystalline lanthanoid partitioning is a natural crystal-chemical observation, not a laboratory separation process. Distinct from bainbridgeite-(YCe), alicewilsonite-(YCe), mckelveyite-(Y), and elemental neodymium or cerium; no criticality designation, microbial mechanism, or recovery yield is asserted.

Explore across X-Mech: MediaIngredientMech · CultureMech · CommunityMech · HabitatMech · TraitMech · CMMMech Network Graph

Record source: data/records/bainbridgeite-ndce.yaml