How does high lattice enthalpy affect the stability of a solid?

High lattice enthalpy is a measure of the strength of the forces between the ions in an ionic solid. When the lattice enthalpy is high, it indicates that the ions are held together very strongly in the crystal lattice. This stability arises because high lattice enthalpy is associated with smaller ionic radii and higher charges on the ions.

When ions are charged, they experience greater electrostatic attraction when they are closer together. Thus, if both the charge of the ions is high (such as in the case of magnesium oxide, MgO, which has divalent cations and anions), it results in a significant increase in lattice enthalpy. Similarly, smaller ionic sizes reduce the distance between ions, further strengthening the electrostatic interactions. As a result, the solid structure becomes more stable due to the strong forces holding the ions in place.

In summary, a high lattice enthalpy reflects strong attractive forces between ions that arise from high charges and short distances, leading to a more stable solid structure. This contributes to the overall stability of the compound, making it less likely to disintegrate or dissolve in solution.