Inert gas
（重定向自Inert atmosphere）
An inert gas is a gas which does not undergo chemical reactions under a set of given conditions. The noble gases often do not react with many substances. Inert gases are used generally to avoid unwanted chemical reactions degrading a sample. These undesirable chemical reactions are often oxidation and hydrolysis reactions with the oxygen and moisture in air. The term inert gas is context-dependent because several of the noble gases can be made to react under certain conditions.