1.Nature:It is tasteless odorless,not combustion,or combustion under normal circutances,is an  insert gas.

2.Useless:It is for low-temperature superconducing technolgy and the cold source.Can also be used as high vacuum devices,atomic reactors,such as the spacecraft leak detection agents and magnesium,zirconium,aluminium,titanium and other welding the protection of gas, GC also be used for the analysis of the carrier gas,the ballon inflated,with the protection of arc welding gas,mixed gas diving with the thermometer and gas filled.