thallium
/ˈθælɪəm/noun
mass noun
- the chemical element of atomic number 81, a soft silvery-white metal which occurs naturally in small amounts in iron pyrites, sphalerite, and other ores. Its compounds are very poisonous. (Symbol: Tl)（化学元素）铊（符号：Tl）。
词源
mid 19th cent.: modern Latin， from Greek thallos 'green shoot'， because of the green line in its spectrum.