H

Heat of Crystallization

ΔH_cryst = −ΔH_fus
Quick Reference
Formula / NotationΔH_cryst = −ΔH_fus
Also Known AsEnthalpy of crystallization, latent heat of crystallization, heat of solidification, heat of freezing

What is Heat of Crystallization?

The heat of crystallization (enthalpy of crystallization) is the heat released when a substance transitions from a liquid (or solution) to a crystalline solid. It is equal in magnitude but opposite in sign to the heat of fusion. This energy is released as the molecules organize into an ordered crystalline lattice. It is an exothermic process.

Formula & Notation

ΔH_cryst = −ΔH_fus

Other Names / Synonyms: Enthalpy of crystallization, latent heat of crystallization, heat of solidification, heat of freezing

Properties & Characteristics

ΔH_cryst = −ΔH_fus. Water: ΔH_cryst = −334 J/g = −6.02 kJ/mol. Exothermic (heat released to surroundings). Temperature remains constant during crystallization (at melting point). Sodium acetate trihydrate releases heat on crystallization — used in hand warmers.

Uses & Applications

Heat pack and hand warmer technology (sodium acetate). Industrial crystallization processes. Purification by recrystallization. Understanding frost formation. Crystal growth technology. Phase change materials for thermal energy storage. Concrete hydration (is a form of crystallization).

Safety Information

Supercooled liquids that crystallize suddenly can release significant heat. Industrial crystallization equipment must manage heat removal. Recrystallization solvents may be flammable or toxic.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Heat of Crystallization
Formula ΔH_cryst = −ΔH_fus
Synonyms Enthalpy of crystallization, latent heat of crystallization, heat of solidification, heat of freezing

Frequently Asked Questions

The heat of crystallization (enthalpy of crystallization) is the heat released when a substance transitions from a liquid (or solution) to a crystalline solid. It is equal in magnitude but opposite in sign to the heat of fusion. This energy is released as the molecules organize into an ordered crystalline lattice. It is an exothermic process.

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