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 w