Question

Write a short note on inorganic benzene.

Answer 1

Inorganic Benzene

• It is a cyclic compound having $12$ sigma and $3$ pi bonds with arrangement of three alternate $\mathrm{BH}$ and $\mathrm{NH}$ units.
• The chemical named Borazine is configured as Inorganic Benzene whose chemical formula is ${\mathbf{B}}_{\mathbf{3}}{\mathbf{N}}_{\mathbf{3}}{\mathbf{H}}_{\mathbf{6}}$ .

Preparation of Inorganic Benzene

• By heating the compounds formed by the reaction of Diborane $\left({\mathrm{B}}_2{\mathrm{H}}_6\right)$ with Ammonia $\left({\mathrm{NH}}_3\right)$ at an elevated temperature of $473K$.
• $\underset{\mathrm{Diborane}}{\underbrace{3{\mathrm{B}}_2{\mathrm{H}}_6}}\left(\mathrm{g}\right)+\underset{\mathrm{Ammonia}}{\underbrace{6{\mathrm{NH}}_3}}\left(\mathrm{l}\right)\stackrel{\mathrm{Low}\mathrm{Yeild}}{\to }\underset{\mathrm{Additional}\mathrm{Compound}}{\underbrace{3{\left[{\mathrm{BH}}_2{\left({\mathrm{NH}}_3\right)}_2\right]}^{+}{\left[{\mathrm{BH}}_4\right]}^{-}}}\stackrel{474\mathrm{K}}{\to }2\underset{\mathrm{Borazine}}{\underbrace{{\mathrm{B}}_3{\mathrm{N}}_3{\mathrm{H}}_6}}\left(\mathrm{l}\right)+\underset{\mathrm{Hydrogen}}{\underbrace{12{\mathrm{H}}_2}}\left(\mathrm{g}\right)$

Properties of Inorganic Benzene

• It is isosteric (same number of atoms) and isoelectronic (same number of electrons) with benzene.
• The atoms of borazine are $s{p}^2$ hybridized.
• Borazine is considered as inorganic benzene as it has same structure as that of benzene i.e. it is isostructural.
• It is a colorless in appearance and found in liquid state.