It is commonly called borecole. It was first prepared by A. Stock in 1926 by reacting B₂H₂ and NH₃ in the ratio at 250-300⁰C.

(i)    3B₂H₆ + 6NH₃  → 2B₃N₃H₆ + 12H₂
                                     (Borazine)

It is also known as inorganic benzene because its physical properties closely reassemble those benzene with which is electronic. It is also prepared by the reduction of boron trichloride which is first converted into trichloroderivative of borazine an then reduced with NaBH₄.
 
                         150⁰C,C₆H₅CI
(ii)   3BCI₃ + 3NH₄CI   →    B₃N₃H₃CI₃
                                     -9HCI

                                   (C₄H₉)₂O
B₃N₃H₃CI₃ + 3NaBH₄    →    B₃N₃H₆ + 1.5B₂H₆
                                    -3NaCI

(iii)  It is also prepared by the direct reaction of NaBH₄ with ammonium chloride :

                              triglyme
3NaBH₄ + 3NH₄CI   →     B₃N₃H₆ + 3NaCI + 9H₂

Borazine has a planar hexagonal ring structure in which B and N atoms are sp² hybridized. An important difference form benzene is that in borazine the π-bond is a dative bond, formed by the overlap of filled 2p^- orbitals of nitrogen with empty 2p orbitals of boron.

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