Thallium(I) chloride
Encyclopedia
Thallium chloride is the chemical compound
with the formula Tl
Cl
. This colourless solid is an intermediate in the isolation of thallium from its ores. Typically, an acidic solution of thallium(I) sulfate
is treated with hydrochloric acid
to precipitate insoluble thallium(I) chloride. This solid crystallizes in the caesium chloride
motif.
The low solubility of TlCl is exploited in chemical synthesis: treatment of metal chloride complexes with TlPF6, gives the corresponding metal hexafluorophosphate
derivative. The resulting TlCl precipitate is separated by filtration of the reaction mixture. The overall methodology is similar to the use of AgPF6, except that Tl+ is much less oxidizing.
The crystalline structure is of cubic CsCl
type at room temperature, but it lowers to the orthorombic thallium iodide
type upon cooling, the transition temperature being likely affected by the impurities .
A very rare mineral lafossaite, Tl(Cl,Br), is a natural form of thallium(I) chloride.
Thallium(I) chloride, like all thallium compounds, is highly toxic, although its insolubility limits its toxicity to a degree.
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
with the formula Tl
Thallium
Thallium is a chemical element with the symbol Tl and atomic number 81. This soft gray poor metal resembles tin but discolors when exposed to air. The two chemists William Crookes and Claude-Auguste Lamy discovered thallium independently in 1861 by the newly developed method of flame spectroscopy...
Cl
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
. This colourless solid is an intermediate in the isolation of thallium from its ores. Typically, an acidic solution of thallium(I) sulfate
Thallium(I) sulfate
Thallium sulfate , archaically known as thallous sulfate, is the sulfate salt of thallium. It is colorless, odorless, and tasteless, but highly toxic.-Uses:...
is treated with hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....
to precipitate insoluble thallium(I) chloride. This solid crystallizes in the caesium chloride
Caesium chloride
Caesium chloride is the inorganic compound with the formula CsCl. This colorless solid is an important source of caesium ions in a variety of applications. Its crystal structure forms a major structural type where each caesium ion is coordinated by 8 chlorine ions...
motif.
The low solubility of TlCl is exploited in chemical synthesis: treatment of metal chloride complexes with TlPF6, gives the corresponding metal hexafluorophosphate
Hexafluorophosphate
Hexafluorophosphate is an anion with chemical formula of . This octahedral species is isoelectronic with sulfur hexafluoride, SF6, and is valence isoelectronic with the highly stable superacid anion fluoroantimonate . As a non-coordinating anion, it is a poor nucleophile...
derivative. The resulting TlCl precipitate is separated by filtration of the reaction mixture. The overall methodology is similar to the use of AgPF6, except that Tl+ is much less oxidizing.
The crystalline structure is of cubic CsCl
Caesium chloride
Caesium chloride is the inorganic compound with the formula CsCl. This colorless solid is an important source of caesium ions in a variety of applications. Its crystal structure forms a major structural type where each caesium ion is coordinated by 8 chlorine ions...
type at room temperature, but it lowers to the orthorombic thallium iodide
Thallium iodide
Thallium iodide can refer to:* Thallium iodide , TlI* Thallium iodide , TlI3* Thallium iodide , TlI4...
type upon cooling, the transition temperature being likely affected by the impurities .
A very rare mineral lafossaite, Tl(Cl,Br), is a natural form of thallium(I) chloride.
Thallium(I) chloride, like all thallium compounds, is highly toxic, although its insolubility limits its toxicity to a degree.