thallium

[thal-ee-uh m]

noun Chemistry.

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; atomic weight: 204.37; atomic number: 81; specific gravity: 11.85 at 20°C.

Origin of thallium

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

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for thallium

Historical Examples of thallium

We will now remove the thallium and put a bit of silver in its place.
Six Lectures on Light
John Tyndall
The simplest curve of this type will be obtained when only one compound is formed, as is the case with mercury and thallium.
The Phase Rule and Its Applications
Alexander Findlay
The thallium papers show that the greatest effect is in the daytime, the iodide papers that it is at night.
Scientific American Supplement No. 275
Various
The iodide curve follows closely that of relative humidity, clouds, and rain; the thallium curve stands in no relation to it.
Scientific American Supplement No. 275
Various
They are not absolutely insoluble in water, and the sulphide of thallium being brown, would probably be damaged by impure air.
Field's Chromatography
George Field

British Dictionary definitions for thallium

thallium

noun

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

Word Origin for thallium

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

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for thallium

rare metallic element, 1861, Modern Latin, from Greek thallos "young shoot, green branch" (see thallus) + element name ending -ium. So called by its discoverer, Sir William Crookes (1832-1919), from the green line in its spectrum by which he detected it.

thallium in Medicine

thallium

[thăl′ē-əm]

n. Symbol Tl

A soft, malleable, highly toxic metallic element whose radioisotopes are used in diagnostic imaging. Atomic number 81.

thallium in Science

thallium

[thăl′ē-əm]

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. See Periodic Table.