Liquid nitrogen

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Liquid nitrogen (LIN) is an inert, colorless, odorless, non-corrosive, nonflammable and very cold substance.

Nitrogen makes up the major portion of the atmosphere (78.03% by volume, 75.5% by weight). Nitrogen is inert and will not support combustion; however, it is not life supporting. Nitrogen is inert except when heated to very high temperatures where it combines with some of the more active metals, such as lithium and magnesium, to form nitrides. It will also combine with oxygen to form oxides of nitrogen and, when combined with hydrogen in the presence of catalysts, will form ammonia. ^[1]

Physical Properties

• Molecular weight: 28.01
• Boiling point @ 1 atm: -320.5°F (-195.8°C, 77°K)
• Freezing point @ 1 atm: -346.0°F (-210.0°C, 63°K)
• Critical temperature: -232.5°F (-146.9°C)
• Critical pressure: 492.3 psia (33.5 atm)
• Density, liquid @ BP, 1 atm: 50.45 lb/scf
• Density, gas @ 68°F (20°C), 1 atm: 0.0725 lb/scf
• Specific gravity, gas (air=1) @ 68°F (20°C), 1 atm: 0.967
• Specific gravity, liquid (water=1) @ 68°F (20°C), 1 atm: 0.808
• Specific volume @ 68°F (20°C), 1 atm: 13.80 scf/lb
• Latent heat of vaporization: 2399 BTU/lb mole
• Expansion ratio, liquid to gas, BP to 68°F (20°C): 1 to 694^[1]

References

1. http://safety.seas.harvard.edu/services/nitrogen.html