Does diamond conduct electricity?

• A. Yes
• B. No
• C. Only when melted
• D. Only at high temperature

Answer: (B)

Diamond is a giant covalent lattice in which each carbon forms four strong bonds to its neighbours in a rigid 3D network. The electrons are tied up in those bonds and there are no delocalized electrons or mobile ions to move and carry charge. Because of this lack of free charge carriers, no electric current can flow, so diamond does not conduct electricity.

That’s why the statement “No” is the best answer. The other ideas aren’t right because simply melting or heating a covalent network doesn’t create free charge carriers like a metal does, so conductivity remains essentially absent in pure diamond.