measured energy changes
There are a number of different ways to measure the strength of a given crystal lattice. One way would be to measure the amount of energy needed to completely pull apart an ionic substance into isolated ions. This value, known as the lattice energy , cannot be measured directly, but it can be calculated based on measured energy changes for other more feasible processes. The lattice energy of an ionic solid provides us with one way to measure the relative strength of the ionic bonds in that compound. Table below shows the lattice energies for various ionic substances:.