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Ionic compounds - EdexcelThe ionic lattice

When a metal element reacts with a non-metal element an ionic compound is formed. They have a giant lattice structure with strong ionic bonds. A lot of energy is needed to overcome these bonds.

Part of Combined ScienceKey concepts in chemistry

The ionic lattice

A regular arrangement of ions

The in a solid are not randomly arranged. Instead, they have a regular, repeating arrangement called an . The lattice is formed because the ions attract each other and form a regular pattern with oppositely ions next to each other.

Sodium and chloride ions tightly packed in rows and columns.
Figure caption,
A two-dimensional model for the ionic lattice in sodium chloride

Remember that the lattice arrangement is giant - for example, a single grain of salt may contain 1.2 脳 1018 (1,200,000,000,000,000,000) ions. The lattice arrangement continues in three dimensions. This is why solid ionic compounds form crystals with regular shapes.

Ionic structure of sodium chloride forming a cubic lattice
Figure caption,
A three-dimensional model for the ionic lattice in sodium chloride

Ionic bonds

The ionic lattice is held together by . In three-dimensional models, ionic bonds are shown as straight lines between ions. This is to keep things simple because ionic bonds can act in any direction.

Ionic bonds are strong between oppositely charged ions.