In chemistry, the lattice energy is the energy change upon formation of one mole of a crystalline ionic compound from its constituent ions, which are assumed to initially be in the gaseous state.  It is a measure of the cohesive forces that bind ionic solids.  The size of the lattice energy is connected to many other physical properties including solubility, hardness, and volatility.  Since it generally cannot be measured directly, the lattice energy is usually deduced from experimental data via the Born–Haber cycle.