On Feb 28, 1:06, Ethan Dicks wrote: Dunno. Perhaps it never did, but that's the systmatic nomenclature form. To be fair, though, the systematic names are more useful for more complex molecules, where there would otherwise be amiguity. Why do you think I didn't use that example? :-) Or molybdenium, tantalium, lanthanium. There are 65 elements whose names end in "ium", only four that end in "um" not "ium", and just one that varies according to geography :-) -- Pete Peter Turnbull Network Manager University of York