What is the term for the change of a substance from a gas directly to a solid without passing through the liquid state?

The term for the change of a substance from a gas directly to a solid without passing through the liquid state is "deposition." This process occurs when vapor molecules lose energy and bond together to form a solid phase. Deposition is commonly observed in natural phenomena, such as the formation of frost, where water vapor in the air transforms directly into ice on cold surfaces.

This phase transition is crucial in various scientific fields, including meteorology and materials science. The opposite of deposition is sublimation, where a solid transforms directly into a gas. Understanding deposition is important for applications like freeze-drying, where moisture is removed from products without going through the liquid phase, preserving the material's structure and nutritional content.