Chemistry:Thallium(I) sulfate

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Thallium(I) sulfate
Thallium(I) sulfate
Other names
Thallous sulfate, Thallium sulfate
3D model (JSmol)
RTECS number
  • XG6800000
UN number 1707
Molar mass 504.83 g/mol
Appearance white prisms or dense white powder
Odor odorless
Density 6.77 g/cm3
Melting point 632 °C (1,170 °F; 905 K)
2.70 g/100 mL (0 °C)
4.87 g/100 mL (20 °C)
18.45 g/100 mL (100 °C)
−112.6·10−6 cm3/mol
GHS pictograms GHS06: ToxicGHS07: HarmfulGHS08: Health hazardGHS09: Environmental hazard
GHS Signal word Danger
H300, H315, H372, H411
P260, P264, P270, P273, P280, P301+310, P302+352, P314, P321, P330, P332+313, P362, P391, P405, P501
NFPA 704 (fire diamond)
Flammability code 0: Will not burn. E.g. waterHealth code 4: Very short exposure could cause death or major residual injury. E.g. VX gasReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no codeNFPA 704 four-colored diamond
Lethal dose or concentration (LD, LC):
16 mg/kg (rat, oral)
23.5 mg/kg (mouse, oral)[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Thallium(I) sulfate (Tl2SO4) or thallous sulfate is the sulfate salt of thallium in the common +1 oxidation state, as indicated by the Roman numeral I. It is often referred to as simply thallium sulfate.[2]


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 rodenticides.[3] 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(I) sulfide (Tl2S), which exhibits high electrical conductivity when exposed to infrared light.


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


Tl2SO4 adopts the same structure as K2SO4. In aqueous solution, the thallium(I) cations and the sulfate anions are separated and highly solvated. Thallium(I) sulfate crystals have a C2 symmetry.


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 and sodium 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 to control the rodent population; it is suspected that in the 1950s, this resulted in the disappearance of the brown fish owl.[4]



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