the work required to separate the particles forming a crystal lattice an infinite distance from each other. Lattice energy is a specific case of binding energy. It depends on the nature of the particles (molecules, atoms, ions) that make up the crystal lattice and on the nature of the interaction between them. Its value ranges from 10 to 4,000 kilojoules/mole and may be determined indirectly by given calorimetric measurements (seeTHERMOCHEMISTRY) and other methods.

Lattice energy also depends on the initial energy of the particles forming the crystal lattice, sometimes referred to as the dependence of lattice energy on temperature. The lattice energy is usually considered when a substance is in the standard state or at 0°K. It largely determines the strength of the bond between the particles in a crystal, as well as the physical properties of the crystal, such as strength, hardness, and melting point.