 thumb|liquid nitrogen thumb|a demonstration of liquid nitrogen at the freeside maker space in atlanta, georgia during the online news association conference in 2013  liquid nitrogen is nitrogen in a liquid state at an extremely low temperature. it is produced industrially by fractional distillation of liquid air. liquid nitrogen is a colorless clear liquid with density of 0.807 g/ml at its boiling point and a dielectric constant of 1.43. liquid nitrogen is often referred to by the abbreviation, ln2 or "lin" or "ln" and has the un number 1977. liquid nitrogen is a diatomic liquid meaning the diatomic character of the covalent n bonding in n2 gas is retained even after liquefaction. at atmospheric pressure, liquid nitrogen boils at  and is a cryogenic fluid that can cause rapid freezing on contact with living tissue. when appropriately insulated from ambient heat, liquid nitrogen can be stored and transported, for example in vacuum flasks. here, the very low temperature is held constant at 77&nbsp;k by slow boiling of the liquid, resulting in the evolution of nitrogen gas. depending on the size and design, the holding time of vacuum flasks (dewars) ranges from a few hours to a few weeks. the development of pressurised super-insulated vacuum vessels have enabled liquefied nitrogen to be stored and transported over longer time periods with losses reduced to 2% per day or less.data book for cryogenic gases and equipment. aspenycap.org liquid nitrogen can easily be converted to a solid by placing it in a vacuum chamber pumped by a rotary vacuum pump. liquid nitrogen freezes at . despite its reputation, liquid nitrogen's efficiency as a coolant is limited by the fact that it boils immediately on contact with a warmer object, enveloping the object 
Coolants Industrial_gases Medical_equipment Nitrogen