Deposition

In-depth explanation of Deposition

Deposition is the direct change of a substance from gas to solid, the reverse of sublimation. It occurs when a vapour is cooled below its frost point without first condensing into a liquid. The process releases heat equal to the enthalpy of sublimation, which is the sum of the enthalpies of vaporization and fusion. Deposition is responsible for frost forming on cold surfaces and for snow crystals forming in clouds. It is also used in industry to produce thin films of solid materials from vapour.

Going deeper: Deposition

Key ideas: Deposition releases ΔHsub in magnitude, which for water is about 51 kJ/mol, equal to the sum of condensation and freezing enthalpy. It happens when the surface is below the frost point and the vapour partial pressure is above the sublimation pressure. Chemical vapour deposition is a related industrial method for thin films.

Common mistakes and connections: A common mistake is calling frost frozen dew; true frost comes from deposition, whereas frozen dew forms by freezing liquid droplets. Another is confusing deposition with sediment deposition in geology or electrodeposition in electrochemistry. Linked to sublimation, phase diagrams and water vapour in the atmosphere.

Visualization of Deposition

Deposition is gas going straight to solid, as frost forms on cold surfaces when water vapour falls below its frost point. The interactive lesson shows this as a live animation or chart.

Worked example and use case

Frost forms on a window on a cold night as water vapour in the air deposits directly as ice crystals.

Where Deposition fits in States of Matter & Solutions

Deposition is topic 49 of 109 in States of Matter & Solutions.

Related topics

• Enthalpy of FusionIntermediate
• Heating CurveBeginner
• SublimationBeginner
• Phase DiagramIntermediate
• Triple PointIntermediate
• Critical PointIntermediate

Browse all 109 topics in States of Matter & Solutions