thulium -
A metallic chemical element symbol Tm with an atomic number of 69.
Wikipedia
Thulium is a chemical element that has the symbol Tm and atomic number 69. Thulium is the least abundant of the lanthanides (promethium is less abundant than thulium, but it is not found naturally on Earth). It is an easily workable metal with a bright silvery-gray luster.
OmegaWiki Dictionary
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thulium Chemical element with symbol Tm and atomic number 69, silvery white lanthanide.
