The simple substance of chlorine at room temperature is chlorine, which is a light green toxic gas, Cl2, consisting of two chlorine atoms. When the pressure is1.01×105pa, it is cooled to -34.6℃ and becomes liquid chlorine. Liquid chlorine is continuously cooled to-10 1℃ and becomes solid chlorine.
In order to convert gaseous chlorine into liquid chlorine, the temperature must be lowered. Common cooling equipment includes: low temperature and ultra-low temperature freezer (-10℃ ~-152℃), negative pressure air cooler and freezer (-4℃ ~ -30℃).