Acetylene:Molecular formula C2H2, structured HC ≡ CH. Colorless gas. Density: 1.173Kg/m3. Melting point:-81.8℃. Sublimation point:-83.6℃. It is soluble in acetone. Explosible mixture can be made by mixing acetylene with air. It is stored within acetone-contained steel cylinder to become soluble acetylene.
It is mainly applied to cut metals.
Quality standard of soluble acetylene accords with National standard GB6819-2004.
Index: acetylene purity %（V/V）≥98.0. Acetylene net weight: (Kg) 5～6. Content of phosphine and sulfureted hydrogen: they won’t make silver nitrate test paper change color or will make the paper turn pale yellow.

Oxygen: Molecular formula: Ｏ2. Colorless gas. Density: 1.429Kg/M3. Melting point:-218.4℃. Boiling point:-183℃. It can be liquefied and solidified. Liquid oxygen is sky-blue and slightly soluble in water.
Main applications: Applied with soluble acetylene together to cut metals. Another application, it is used in medical health service.
Specification index: O2%≥99.5 Filling pressure within cylinder Pa 13～15MPa

Nitrogen: Molecular formula: N2, smell-less gas. Density 1.2506Kg/M3. Melting point: -209.86℃, Boiling point: -195.8℃. Lightly soluble in water and ethanol. Its chemical property is active.
Applications: It is mainly used to ?manufacture nitric acid, synthetic ammonia, calcium cyanamide, chargeable battery bulb and protective gas for oxidization prevention, volatilization prevention and flammable substances. In other side, liquid nitrogen can be used as coolant for deep freezing of apparatus or machine accessories.
Index: N2 % ≥99.99. Filling pressure MPa 14.7～15.0