thallium

[ thal-ee-uh m ]

/ ˈθæl i əm /

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.

Nearby words

thalia, thalidomide, thalli, thallic, thallious, thallium, thallium sulfate, thallo-, thalloid, thallophyte, thallous

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. 2019

Examples from the Web for thallium

If we add to the silver in our camera a bit of thallium, we shall obtain the light of both metals.
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 current first selects as its carrier the most volatile metal, which in this case is thallium.
Fragments of science, V. 1-2|John Tyndall
On chromate of cadmium, made with bichromate of potash, thallium would naturally confer an orange hue.
Field's Chromatography|George Field

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

British Dictionary definitions for thallium

thallium

/ (ˈθælɪəm) /

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

Medicine definitions for thallium

thallium

[ thăl′ē-əm ]

n. Symbol Tl

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

Science definitions for thallium

thallium

[ thăl′ē-əm ]

Tl

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.