Sublimation
The direct phase transition of a substance from solid to gas state without passing through an intermediate liquid phase.
Governing formula
ΔH_sub = ΔH_fus + ΔH_vap
SI unit
J/kg or J/mol
In depth
Occurs at temperatures and pressures below the substance's triple point in a phase diagram.
Examples in the real world
Dry ice (solid $CO_2$) sublimating directly into $CO_2$ gas at atmospheric pressure (-78.5°C), or freeze-drying food.