Why is diamond so hard?
Diamond is extremely hard because it is a giant covalent structure in which every carbon atom is strongly bonded to four others.
GCSE Chemistry
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
In more detail
Each carbon atom in diamond forms four strong covalent bonds arranged in a rigid three-dimensional lattice. There are no weak points and no layers that can slide, so a huge number of strong covalent bonds must be broken to deform or melt it. This also gives diamond its very high melting point.
Key points for the exam
- Giant covalent (macromolecular) structure.
- Each carbon covalently bonded to 4 others in a rigid lattice.
- Many strong covalent bonds must be broken → hard, high melting point.
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