Diboron Tetrachloride

Diboron tetrachloride, also known as boron chloride oxide or boron oxychloride, is a compound with the chemical formula B2Cl4. It is a colorless liquid at room temperature and pressure.

Diboron tetrachloride is prepared by reacting boron trichloride with oxygen gas. The reaction is exothermic and occurs at high temperatures:

2BCl3 + O2 → B2Cl4 + O2Cl2

The compound has a tetrahedral molecular geometry, with each boron atom bonded to two chlorine atoms and one oxygen atom. The O-Cl bond length is longer than the Cl-B bond length due to the higher electronegativity of oxygen compared to boron.

Diboron tetrachloride is a Lewis acid and can react with Lewis bases to form adducts. For example, it reacts with ammonia to form the adduct B2Cl4(NH3)2.

The compound is used as a reagent in organic synthesis, particularly in the preparation of boron-containing compounds such as boronic acids and esters. It is also used as a catalyst in some reactions. However, diboron tetrachloride is highly toxic and corrosive, and should be handled with care.