Thallium is the chemical element in the periodic table that has the symbol Tl and atomic number 81. This soft gray malleable poor metal resembles tin but discolors when exposed to air. Thallium is highly toxic and is used in rat poisons and insecticides but since it might also cause cancer (although the EPA does not class it as carcinogen), this use has been cut back or eliminated in many countries. It is also used in infrared detectors.

Notable characteristics

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This metal is very soft and malleable and can be cut with a knife. When it is first exposed to air, thallium has a metallic luster but quickly tarnishes with a bluish-gray tinge that resembles lead (it is preserved by keeping it under oil). A heavy layer of oxide builds up on thallium if left in air. In the presence of water, thallium hydroxide is formed.

Applications

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The odorless and tasteless thallium sulfate was widely used in the past as a rat poison and ant killer. In the United States and many other countries this use is no longer allowed due to safety concerns. Other uses:

• thallium sulfide's electrical conductivity changes with exposure to infrared light therefore making this compound useful in photocells.
• thallium bromide-iodide crystals have been used as infrared optical materials.
• thallium oxide has been used to manufacture glasses that have a high index of refraction.
• used in semiconductor materials for selenium rectifiers,
• in gamma radiation detection equipment,
• high-density liquid used for sink-float separation of minerals,
• used in the treatment of ringworm and other skin infections. However this use has been limited due to the narrow margin that exists between toxicity and therapeutic benefit.
• radioactive thallium-201 is used for diagnostic purposes in nuclear medicine, particularly in stress tests used for risk stratification in patients with coronary artery disease (CAD).
• combined with sulfur or selenium and arsenic, thallium has been used in the production of high-density glasses that have low melting points in the range of 125 and 150 °C. These glasses have room temperature properties that are similar to ordinary glasses and are durable, insoluble in water and have unique refractive indexes.
• thallium amalgam is used in thermometers for low temperature, because it freezes at -58 °C (pure mercury freezes at -38 °C).

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Newtown (stop 3) Decapitated by Tram (stop 10) Funeral Service in Middle of Road (stop 32) Thallium poisoner (stop 37) The Samson of Newtown
NatTrustEd (NT NSW Education) Fri, 08 Jan 2010 00:47:09 -0000
Newtown (stop 3) Decapitated by Tram (stop 10) Funeral Service in Middle of Road (stop 32) Thallium poisoner (stop 37) The Samson of Newtown
Thallium distinctive voice recognition in android phone stop it sometimes works food stamp
JacoboTarrio (Jacobo Tarrio) Thu, 07 Jan 2010 03:24:04 -0000
Thallium distinctive voice recognition in android phone stop it sometimes works food stamp
@Thallium 没有~ 谁来的
a_mango (Shirley Yip) Wed, 06 Jan 2010 02:35:03 -0000
@Thallium 没有~ 谁来的
@Thallium 是的
a_mango (Shirley Yip) Wed, 06 Jan 2010 02:10:51 -0000
@Thallium 是的
Here are some interesting contaminents the city says are in my drinking water: Arsenic, Thallium, and "Alpha Particle Activity" (radiation).
Caes (Kevin) Mon, 04 Jan 2010 22:19:06 -0000
Here are some interesting contaminents the city says are in my drinking water: Arsenic, Thallium, and "Alpha Particle Activity" (radiation).
@Thallium 天阿天阿~
a_mango (Shirley Yip) Mon, 04 Jan 2010 08:58:42 -0000
@Thallium 天阿天阿~

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