Mckelveyite group minerals – Part 1: Nomenclature and new data on donnayite-(Y)

Abstract. The mckelveyite group consisting of seven carbonate minerals – mckelveyite-(Y), ewaldite, weloganite, donnayite-(Y), alicewilsonite-(YCe), alicewilsonite-(YLa), and bainbridgeite-(YCe) is formally established. general formula the A3B3(CO3)6 ⋅ 3H2O, where A= Na, Ca, Y, Zr B= Sr, Ba, Ce, La. Different order–disorder modifications are known resulting in triclinic, monoclinic, hexagonal, trigonal with essentially same structure. Re-examination donnayite-(Y) type specimens shows that original description contains data collected on two different species: alicewilsonite-(YCe). Donnayite-(Y), NaCaSr3Y(CO3)6 was found only one specimen out CMNMC 39396 housed at Canadian Museum Nature, Ottawa. This becomes holotype donnayite-(Y). crystal structure solved refined to R1= 0.055 for 3366 reflections I>2σ(I). Donnayite-(Y) shown have a weloganite-type confirming its place group.