thallium

[thal-ee-uhm]

noun

Chemistry.

1. a soft, malleable, rare, bluish-white metallic element: used in the manufacture of alloys and, in the form of its salts, in rodenticides. Tl; 204.37; 81; 11.85 at 20°C.

thallium

/ ˈθælɪəm /

noun

1. a soft malleable highly toxic white metallic element used as a rodent and insect poison and in low-melting glass. Its compounds are used as infrared detectors and in photoelectric cells. Symbol: Tl; atomic no: 81; atomic wt: 204.3833; valency: 1 or 3; relative density: 11.85; melting pt: 304°C; boiling pt: 1473±10°C

thallium

1. A soft, malleable, very poisonous metallic element that is used in photography, in making low-melting and highly refractive glass, and in treating skin infections. Atomic number 81; atomic weight 204.38; melting point 303.5°C; boiling point 1,457°C; specific gravity 11.85; valence 1, 3.

2. See Periodic Table

Word History and Origins

Origin of thallium¹

1860–65; < New Latin, equivalent to thall- (< Greek thallós green stalk) + -ium -ium; named after green line in its spectrum

Word History and Origins

Origin of thallium¹

C19: from New Latin, from Greek thallos a green shoot; referring to the green line in its spectrum

Example Sentences

There are many recorded cases of fatal thallium poisoning.

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Much of the thallium in the Baltic Sea, the largest human-induced hypoxic area on Earth, accumulates in the sediment thanks to abundant sulfide minerals.

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They precisely measured isotopes of the metal thallium trapped in the sediments, which indicate how much oxygen was dissolved in the global ocean at the time the sediments formed.

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Doctors later diagnosed her with thallium poisoning, a soft metal which dissolves in water and is odourless and tasteless.

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Lepidolite extraction and smelting produces toxic by-products like thallium and tantalum that cause severe water pollution, said Wu Wei, an assistant professor at Xiamen University.

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