what is action of halogen on boron
Answers
Answer:
The halides react with water to form boric acid.
All three lighter boron trihalides (BF3, BCl3, and BBr3) form stable adducts with common Lewis bases.
The sequence for the Lewis acidity is BF3 < BCl3 < BBr3,where BBr3 is the strongest Lewis acid. This trend is commonly attributed to the degree of [latex]\pi[/latex] -bonding in the planar boron trihalid that would be lost upon pyramidization of the the BX3molecule.
Boron tribromide (BBr3) is a colorless, fuming liquid that is an excellent demethylating or dealkylating agent.
Boron trichloride (BCl3) is a colorless, dangerously reactive gas that is a valuable reagent in organic synthesis.
Boron trifluoride (BF3) is a pungent, colorless, corrosive, toxic gas that forms white fumes in moist air.
Boron Halides
Boron undergoes halogenation to form trihalides with the molecular structure BX3, as in the following:
[latex]2B + 3Br_2 \rightarrow 2BBr_3[/latex]
In its most familiar compounds, boron has the formal oxidation state III, or +3. These include oxides, sulfides, nitrides, and halides. The trihalides form planar trigonal structures and are Lewis acids because they readily form adducts with electron-pair donors, which are called Lewis bases. For example, fluoride (F–) and boron trifluoride (BF3) combine to give the tetrafluoroborate anion, BF4–. Boron trifluoride is used in the petrochemical industry as a catalyst.
Explanation:
The halides react with water to form boric acid. All three lighter boron trihalides (BF3, BCl3, and BBr3) form stable adducts with common Lewis bases. ... Boron trichloride (BCl3) is a colorless, dangerously reactive gas that is a valuable reagent in organic synthesis.