Liquid nitrogen

Liquid nitrogen is nitrogen at a very low temperature. It is usually produced by a process known as fractional distillation of air. At atmospheric pressure (normal pressure) nitrogen boils at −196 °C (77 K; −321 °F). Nitrogen was first made into a liquid at Jagiellonian University on 15 April 1883. Zygmunt Wróblewski and Karol Olszewski were the first scientists to liquefy nitrogen, oxygen and carbon dioxide.^[1] During World War II the production of liquid nitrogen became common.^[2] This lowered the cost to produce it. After the war new uses were found for liquid gases. Liquid nitrogen became a major gas in the US.^[2]

1. ↑ Cryosurgery: A Practical Manual, ed. Paola Pasquali (Berlin; Heidelberg: Springer Berlin Heidelberg, 2015), p. 7
2. ↑ ^{2.0 2.1} Ebbe Almqvist, History of Industrial Gases (New York; London: Kluwer Academic/Plenum Publishers, 2003), p. 423