Any of a group of rare gases that include helium, neon, argon, krypton, xenon, and radon that exhibit great stability and extremely low reaction rates, also called inert gas.

【化】钝气；又称为惰性气体 inert gas。包括：氦(He)、氖(Ne)、氩(Ar)、氪(Kr)、氙(Xe)、氡(Rn)。