Boron nitride (BN) can exist in several different structural forms, similar to carbon. The two most common forms of boron nitride are hexagonal boron nitride (h-BN) and cubic boron nitride (c-BN), each with its own distinct structure.

1. Hexagonal Boron Nitride (h-BN):

   • In hexagonal boron nitride, the boron and nitrogen atoms are arranged in a hexagonal lattice similar to graphene.
   • Each boron atom is bonded to three nitrogen atoms, and each nitrogen atom is bonded to three boron atoms.
   • The bonding is primarily covalent in nature.
   • It has a layered structure similar to graphite, with strong covalent bonds within the layers and weak van der Waals forces between the layers.
   • h-BN is often referred to as “white graphene” due to its similar structure to graphene and its white color.
   • It is a good electrical insulator and has high thermal conductivity in the plane of its layers.

2. Cubic Boron Nitride (c-BN):

   • Cubic boron nitride has a crystal structure analogous to diamond, where each boron atom is bonded to four nitrogen atoms and vice versa.
   • It forms a three-dimensional network of alternating boron and nitrogen atoms, similar to the carbon atoms in diamond.
   • The bonding in c-BN is predominantly covalent, resulting in a very hard material.
   • It is often used as an abrasive in tools and coatings due to its hardness, second only to diamond.
   • c-BN is also known as “borazon.”

Both hexagonal and cubic boron nitride have unique properties and applications due to their different structures and bonding characteristics.