Ionic bonds, covalent bonds and metallic bonds are examples of chemical bonds. The structure and bonding in a substance are modeled in different ways, including dot and cross diagrams.
The ionElectrically charged particle, formed when an atom or molecule gains or loses electrons. in a solid ionic compoundAn ionic compound occurs when a negative ion (an atom that has gained an electron) joins with a positive ion (an atom that has lost an electron). are not randomly arranged. Instead, they have a regular, repeating arrangement called an ionic latticeThe regular arrangement of ions in an ionic substance.. The lattice is formed because the ions attract each other and form a regular pattern with oppositely chargeProperty of matter that causes a force when near another charge. Charge comes in two forms, positive and negative. For example, a negative charge causes a repulsive force on a neighbouring negative charge. ions next to each other.
Figure caption,
A two-dimensional model for the ionic lattice in sodium chloride
The lattice arrangement continues in three dimensions. This is why solid ionic compoundA substance formed by the chemical union of two or more elements. can form crystals with regular shapes. A crystal contains very many ions, so the ionic lattice is a ‘giant’ ionic lattice.
Figure caption,
A three-dimensional model for the ionic lattice in sodium chloride
Ionic bonds
The ionic lattice is held together by ionic bondingIonic bonding forms between two atoms when an electron is transferred from one atom to the other, forming a positive-negative ion pair.. In three-dimensional models, ionic bonds are shown as straight lines between ions. This is only to keep things simple, because ionic bonds can act in any direction.