Enthalpy of fusion

The enthalpy of fusion or heat of fusion (Δ_fusH) is the amount of energy required to to make one mole of an element reach its melting point and go from a solid to a liquid state, at constant pressure. In other words, it is the amount of energy that a system can exchange with its surroundings. It is a magnitude of thermodynamics (H), amount of energy that can be exchanged.

The enthalpy of fusion is a latent heat since during the process of change of state there is no appreciable change in temperature. The heat is completely invested in modifying the structure of the material to give mobility to its molecular units. When to study the energy necessary for the change from solid to liquid, reference is made to the unit of mass, the parameter used is the "specific heat of fusion" in cal/g or J/g. However, when one wants to refer to the unit absorbed per mole of substance in change of state, the "enthalpy of fusion" is used in kJ/mol.

Values of enthalpies of fusion of common substances

The values in this table have been obtained from the CRC Manual Handbook of Chemistry and Physics, Edition nº62. The conversion between cal/g and J/g has been carried out taking into account the conversion factor thermochemical 1 calorie = 4,184 joules.
The enthalpy values of fusion (kJ/mol) have been obtained by multiplying the heat of fusion (J/g) by the molecular masses of each substance (g/mol) and divided by a thousand.

Values of the enthalpy of fusion of chemical elements

Values for the elements in standard conditions expressed in in kJ/mol: