Airsensitive

Air-sensitive is an adjective used primarily in chemistry, materials science, and related fields to describe substances that react with components of air, especially oxygen or moisture, or that undergo significant property changes upon exposure. The term signals that exposure to ordinary ambient air can compromise the material, making handling, storage, and transport more complex. Although the concept is common in laboratory settings, it also applies to certain industrial processes and packaged products.

In practice, air-sensitive materials include many organometallic reagents (for example, alkyl lithium and Grignard reagents), some catalysts, and various reactive polymers or metal alloys. These substances are typically kept under inert gas such as nitrogen or argon and are handled with dry, oxygen-free techniques. Common methods include using a glovebox or Schlenk line, applying dry solvents, and sealing glassware to minimize air contact. Storage often involves desiccators, vacuum-sealed containers, or dedicated shelves with controlled atmosphere.

Air sensitivity is related to, but distinct from, moisture sensitivity. Some materials require both oxygen- and moisture-free conditions, while others may be more susceptible to one component of air than the other. In electronics and materials testing, the term may also describe devices whose performance is affected by exposure to air, such as sensors that respond to atmospheric oxygen or humidity.

See also: moisture sensitivity, inert atmosphere, glovebox, Schlenk technique, air sensitivity.