Thallium(I) sulfate (Tl₂SO₄) or thallous sulfate is the

sulfate The sulfate or sulphate ion is a polyatomic ion, polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salt (chemistry), ...

salt of

thallium Thallium is a chemical element with the symbol Tl and atomic number 81. It is a gray post-transition metal that is not found free in nature. When isolated, thallium resembles tin, but discolors when exposed to air. Chemists William Crookes a ...

in the common +1 oxidation state, as indicated by the Roman numeral I. It is often referred to as simply thallium sulfate.

Uses

During the last two centuries, Tl₂SO₄ had been used for various medical treatments but was abandoned. In the later 1900s it found use mainly for

rodenticide Rodenticides are chemicals made and sold for the purpose of killing rodents. While commonly referred to as "rat poison", rodenticides are also used to kill mice, squirrels, woodchucks, chipmunks, porcupines, nutria, beavers, and voles. Despite ...

s. 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 Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, ...

. Tl₂SO₄ is mostly used today as a source of Tl⁺ in the research laboratory. It is a precursor to

thallium(I) sulfide Thallium(I) sulfide, Tl2S, is a chemical compound of thallium and sulfur. It was used in some of the earliest photo-electric detectors by Theodore Case who developed the so-called thalofide (sometimes spelt thallofide) cell, used in early film pr ...

(Tl₂S), which exhibits high electrical conductivity when exposed to

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from aroun ...

light.

Preparation

Thallium(I) sulfate is produced by the reaction of thallium metal with sulfuric acid followed by

crystallization Crystallization is the process by which solid forms, where the atoms or molecules are highly organized into a structure known as a crystal. Some ways by which crystals form are precipitating from a solution, freezing, or more rarely de ...

Structure

Tl₂SO₄ adopts the same structure as K₂SO₄. In aqueous solution, the thallium(I)

cation An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

s and the sulfate

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

s are separated and highly solvated. Thallium(I) sulfate crystals have a C₂ symmetry.

Toxicity

Thallium(I) sulfate is soluble in water and its toxic effects are derived from the thallium(I) cation. The mean lethal dose of thallium(I) sulfate for an adult is about 1 gram. Since thallium(I) sulfate is a simple powder with indistinctive properties, it can easily be mistaken for more innocuous chemicals. It can enter the body by ingestion, inhalation, or through contact with the skin. The thallium(I) cation is very similar to

potassium Potassium is the chemical element with the symbol K (from Neo-Latin '' kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosp ...

and

sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...

cations, which are essential for life. After the thallium ion enters the cell, many of the processes that transport potassium and sodium are disrupted. Due to its poisonous nature, many western countries have banned the use of thallium(I) sulfate in products for home use and many companies have also stopped using this compound. A dosage in excess of 500 mg is reported as fatal. Thallium(I) sulfate, after entering the body, concentrates itself in the kidneys, liver, brain, and other tissues in the body. Thallium(I) sulfate was used in

Israel Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...

to control the rodent population; it is suspected that in the 1950s, this resulted in the disappearance of the brown fish owl.Mendelssohn, H
Ecological effects of chemical control of rodents and jackals in Israel
at LPO Mission Rapaces

Sources

Saha A. Thallium toxicity: A growing concern. Indian J Occup Environ Med 2005;9:53-56

References

External links

( WHO/ FAO)
Kaunas University of TechnologySmithsonian National Zoological ParkISIS Conducting Chemical Weapons Tests on Live Victims
{{Sulfates Thallium(I) compounds Sulfates Rodenticides