Thallium, element 81, was independently discovered in 1861 by British chemist William Crookes and French chemist Claude-Auguste Lamy. Crookes explains the name he bestowed on the element in the 16 March 1861 issue of The Chemical News:
I have thought [...] to propose for it the provisional name of Thallium, from the Greek θαλλός, or Latin thallus, a budding twig [...] which I have chosen as the green line which it communicates to the spectrum recals [sic] with peculiar vividness the fresh colour of vegetation at the present time.1
The chemical symbol for thallium is Tl.
Copyright 1997-2013, by David Wilton