Enthalpy of Fusion
The enthalpy change when one mole of a solid melts to a liquid at its melting point.
Formula / equation
ΔH_fus
Unit
kJ/mol
In depth
Melting only needs to loosen the lattice enough for particles to move past one another, not to separate them entirely, so fusion enthalpy is far smaller than vaporisation enthalpy. Its magnitude reflects the strength of the forces holding the lattice together.
Examples in the real world
Ice needs 6.01 kJ/mol, sodium chloride 28.2 kJ/mol, and tungsten 52.3 kJ/mol.