Pronunciation: (thal'ē-um), [key]
a soft, malleable, rare, bluish-white metallic element: used in the manufacture of alloys and, in the form of its salts, in rodenticides. Symbol: Tl; at. wt.: 204.37; at. no.: 81; sp. gr.: 11.85 at 20°C.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.