Thallium(I) sulfate

Thallium(I) sulfate

Names
Other names Thallous sulfate, Thallium sulfate
Identifiers
CAS Number	7446-18-6 N
3D model (Jmol)	Interactive image
ChemSpider	23218 Y
ECHA InfoCard	100.028.365
KEGG	C18567 N
PubChem	24833
InChI InChI=1S/H2O4S.2Tl/c1-5(2,3)4;;/h(H2,1,2,3,4);;/q;2*+1/p-2 Y Key: YTQVHRVITVLIRD-UHFFFAOYSA-L Y InChI=1/H2O4S.2Tl/c1-5(2,3)4;;/h(H2,1,2,3,4);;/q;2*+1/p-2 Key: YTQVHRVITVLIRD-NUQVWONBAB
SMILES [Tl+].[Tl+].[O-]S([O-])(=O)=O
Properties
Chemical formula	Tl2SO4
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)
Solubility in water	2.70 g/100 mL (0 °C) 4.87 g/100 mL (20 °C) 18.45 g/100 mL (100 °C)
Magnetic susceptibility (χ)	−112.6·10−6 cm3/mol
Refractive index (nD)	1.860
Structure
Crystal structure	rhomboid
Hazards
EU classification (DSD)	T+ N
R-phrases	R28, R38, R48/25, R51/53
S-phrases	(S1/2), S13, S36/37, S45, S61
NFPA 704	0 4 0
Lethal dose or concentration (LD, LC):
LD50 (median dose)	16 mg/kg (rat, oral) 23.5 mg/kg (mouse, oral)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
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. Thallium(I) sulfate is colourless, odourless, tasteless, and highly toxic.

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. 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.