Which type of bonding exists in diamond?

• A. Metallic
• B. Ionic
• C. Covalent network
• D. Hydrogen

Answer: (C)

In diamond, each carbon atom forms four strong covalent bonds with four neighbors, creating a three‑dimensional tetrahedral network. These bonds extend throughout the crystal, making it a giant covalent (covalent network) lattice. This explains its very high melting point, extreme hardness, and poor electrical conductivity, since the electrons are localized in bonds rather than free to move. Metallic bonding would need a sea of delocalized electrons around a lattice of ions, which isn’t the case here; ionic bonding requires transfer of electrons to form charged ions, which doesn’t happen in pure carbon; hydrogen bonding needs hydrogen attached to N, O, or F to form H‑bonds, which isn’t present in diamond. Therefore, the bonding in diamond is covalent network.