Giant Lattice

Summary: A three-dimensional, repeating arrangement of particles held together by strong bonds throughout the entire structure. Tags: igcse chemistry definition bonding Created: 2026-07-14 Last Updated: 2026-07-14

A giant lattice (also called a giant structure) is a three-dimensional, repeating arrangement of atoms, ions, or molecules held together by strong chemical bonds that extend throughout the entire structure, rather than existing as discrete small molecules. Giant ionic lattices, such as sodium chloride, consist of alternating positive and negative ions arranged in a regular pattern held together by strong electrostatic forces in all directions, which gives them high melting points and the inability to conduct electricity unless molten or dissolved in water. Giant covalent lattices, also called macromolecular structures, include diamond — where each carbon atom is tetrahedrally bonded to four others in a three-dimensional network, making it the hardest known natural substance — and silicon dioxide (silica, SiO₂), where each silicon atom bonds to four oxygen atoms in a continuous framework. Giant metallic lattices consist of positive metal ions arranged in a regular array, surrounded by a sea of delocalised electrons that accounts for electrical conductivity, malleability, and the generally high melting points of metals. IGCSE candidates must be able to identify the type of giant structure from a substance’s properties, explain why these structures have high melting and boiling points (strong bonds throughout the entire lattice must be broken), and compare them with simple molecular structures that have low melting points because only weak intermolecular forces, not covalent bonds, are overcome on melting.

Key term — IGCSE Chemistry (0620/0971) glossary.