In chemistry, what occurs when a substance transitions from solid to gas without becoming liquid?

The transition of a substance from solid to gas without passing through the liquid phase is known as sublimation. This process involves the direct conversion of solid particles into gas particles, typically occurring under specific temperature and pressure conditions. A common example of sublimation is the transformation of dry ice (solid carbon dioxide) directly into carbon dioxide gas at room temperature and atmospheric pressure.

Understanding sublimation is critical in various scientific and practical applications, such as freeze-drying processes, where moisture is removed from food products without affecting their structure or taste, and in certain industrial processes where avoiding a liquid phase is essential for efficiency or material stability.

In contrast, condensation refers to the process where a gas turns into a liquid, deposition is the reverse of sublimation where a gas transitions directly to a solid, and evaporation involves the transformation of a liquid into gas, which does not align with the direct solid-to-gas transition characteristic of sublimation.