Thallium(I) sulfate

Thallium(I) sulfate
Thallium(I) sulfate
Other names	Thallous sulfate
Molecular formula	Tl2SO4
Molar mass	504.83 g/mol
CAS number	[7446-18-6]
Density	6.77 g/cm3
Solubility (water)	Soluble
Melting point	632 °C
Boiling point	? °C
EU classification	Highly toxic (T+) Dangerous for the environment (N)
R-phrases	Template:R28, Template:R38, Template:R48/25, Template:R51/53
S-phrases	Template:S1/2, Template:S13, Template:S36/37, Template:S45, Template:S61
Disclaimer and references

Thallium(I) sulfate is Tl₂SO₄. This salt is colorless, odorless, tasteless but highly toxic.

During the last two centuries, Tl₂SO₄ had been used for various medical treatments but was abondoned. In the latter 1900's it found use mainly for rodenticides. These applications were prohibited in 1975 in the US due to the nonselective nature of its toxicity. Thallium(I) sulfate inhibits the growth of plants by preventing germination. Tl₂SO₄ is mostly used today as a source of Tl⁺ in the research laboratory. It is a precursor to thallium sulfide, which exhibits high electrical conductivity when exposed to infrared light.

File:Thallium sulfate.jpg

Toxicity

Thallium(I) Sulfate is soluable in water. Its toxic effects are derived form this dissociation. Since thallium sulfate is a simple powder with indistinctive properties as mentioned above, it is easily mistaken for other chemicals. It can enter the body by ingestion, inhalation, or through contact with the dermis. Once in the body, the salt dissolves. Thallium contains an oxidation state (+1), identical to potassium and sodium, which are subsequently used by the body. Disolved thallium substitutes itself inplace of sodium or potassium in the sodium potassium (Na/K) pump. This occurs by a rather simple mechanism.

Tl₂SO₄ + 2K+ ${\overrightarrow {\leftarrow }}$ K₂SO₄ + 2Tl+

Tl₂SO₄ + 2Na+ ${\overrightarrow {\leftarrow }}$ Na₂SO₄ + 2Tl+

After accessing the cell, many processes that utilize the potassium and sodium are massively disrupted. Because of the ease and simplicity of these reactions, many western countries have banned the use of thallium sulfate in any products used for home use. Many companies have stopped using this compound all together.

A dosage in excess of 500 mg is reported as fatal. Thallium sulfate, after entering the body, concentrates itself in the kidneys, liver, brain, muscle tissue and other tissue in the body.

Thallium sulfate was used in Isreal to control the rodent population. This resulted in the extinction of the Brown Fish Owl in the 1950's

Disposal

Due to the toxic effects and indiscriminate appearance, careful transportation and disposal of those containers must be done with care. Full protection should be taken when transporting canisters. The containers themselves should be disposed of by burning or burial below soil level. They should not be reused.

Availability

Despite the dangerous nature of this compound, it can still be purchased. Manufatures include but are not limited to:

-Kinmet Group--- Guangxi, China

-Umicore Marketing Services--- North Carolina, USA

-NOAH Technologies Corporation--- Texas, USA

-Tinfos Nizi--- Luxembourg, Luxembourg

-Atlantic Equipment Engineers--- New Jersey, USA

Many of these firms supply chemicals to universities for research purposes.

External links

• International Chemical Safety Card 0336
• NIOSH Pocket Guide to Chemical Hazards
• European Chemicals Bureau
• Pesticide Data Sheet (WHO/FAO)
• Kaunas University of Technology
• University of Wisconsin-Madison Chemistry Department
• Smithsonian Naitonal Zoological Park