atomic number 68

Thesaurus

Noun

1.atomic number 68 - a trivalent metallic element of the rare earth group; occurs with yttriumEr, erbiummetal, metallic element - any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.fergusonite - a dark mineral consisting of oxides of yttrium and erbium and tantalum and other mineralsgadolinite, ytterbite - a mineral that is a source of rare earths; consists of silicates of iron and beryllium and cerium and yttrium and erbium