What does the term "pyrophoric" refer to in chemistry?

The term "pyrophoric" specifically refers to a substance that is capable of self-ignition when exposed to air or moisture without the need for an external ignition source. This means that these materials can ignite spontaneously at room temperature, which poses significant safety hazards in handling and storage.

Understanding the context of pyrophoric substances is crucial for safety protocols in chemistry, especially in laboratory and industrial environments. These materials often require special precautions to prevent accidents, such as being stored in inert atmospheres or under specific conditions that minimize exposure to air.

While highly flammable substances also pose a risk, they do not necessarily ignite spontaneously like pyrophorics. Explosive substances, on the other hand, undergo rapid decomposition that produces gas and heat, which is different from the steady ignition characteristic of pyrophorics. Corrosive substances damage materials upon contact but do not typically ignite or exhibit self-ignition behavior.