What typically enhances the lattice enthalpy in solid structures?

Lattice enthalpy is a measure of the strength of the forces between the ions in an ionic solid. It reflects the energy required to separate one mole of an ionic solid into its constituent gaseous ions. The factors that influence lattice enthalpy significantly include the charge of the ions and the distance between them.

A higher charge on the ions leads to stronger electrostatic attractions between the ions. Since the force of attraction is directly proportional to the product of the charges on the ions, increasing the charge will enhance the lattice enthalpy. For example, a divalent cation (like Ca²⁺) will have a stronger attraction to an anion than a monovalent cation (like Na⁺) due to the higher charge.

Additionally, a smaller distance between the ions increases the force of attraction, as electrostatic forces decrease with the square of the distance (Coulomb's Law). Therefore, when ions are closer together, the lattice enthalpy will be greater.

Together, higher charges and shorter distances lead to stronger ionic interactions and, consequently, a more negative (or more favorable) lattice enthalpy value. This is why the correct choice emphasizes both higher charges and smaller distances between ions as the primary factors