Selenium tetrachloride is the inorganic compound

Inorganic compound

Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...

 composed with the formula

Chemical formula

A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....

 SeCl₄. This compound exists as yellow to white volatile solid. It is one of two commonly available selenium chlorides, the other example being selenium monochloride

Selenium monochloride

Selenium monochloride is an inorganic compound with the formula Se2Cl2. Although it is called selenium monochloride, a more descriptive name might be diselenium dichloride. It is a reddish-brown, oily liquid that is hydrolyses slowly. It exists in chemical equilibrium with SeCl2, SeCl4, chlorine,...

, Se₂Cl₂. SeCl₄ is used in the synthesis of other selenium

Selenium

Selenium is a chemical element with atomic number 34, chemical symbol Se, and an atomic mass of 78.96. It is a nonmetal, whose properties are intermediate between those of adjacent chalcogen elements sulfur and tellurium...

 compounds.

Synthesis and structure

The compound is prepared by treating selenium with chlorine: When the reacting selenium is heated, the product sublimes from the reaction flask. The volatility of selenium tetrachloride can be exploited to purification of selenium.

Solid SeCl₄ consists of separated Cl⁻ and [SeCl₃]⁺ centers. The cations are pyramidal consistent with the predictions of VSEPR theory. Gaseous SeCl₄ contains SeCl₂ and chlorine, which recombine upon condensation.

Reactions

Selenium tetrachloride can be reduced in situ to the dichloride using triphenylstibine:

SeCl₄ + SbPh₃ → SeCl₂ + Cl₂SbPh₃

Selenium tetrachloride reacts with water to give selenous

Selenous acid

Selenous acid is the chemical compound with the formula H2SeO3. Structurally, it is more accurately described by 2SeO. It is the principal oxoacid of selenium; the other being selenic acid.-Formation and properties:...

 and hydrochloric

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....

 acid

Acid

An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

s:

SeCl₄ + 3 H₂O → H₂SeO₃ + 4 HCl

Upon treatment with selenium dioxide

Selenium dioxide

Selenium dioxide is the chemical compound with the formula SeO2. This colorless solid is one of the most frequently encountered compounds of selenium.-Properties:...

, it gives selenium oxychloride:

SeCl₄ + SeO₂ → 2SeOCl₂