Liquid oxygen
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Liquid oxygen (also LOx, LOX or Lox in the aerospace industry) is the liquid form of oxygen. It has a pale blue color and is strongly paramagnetic. Liquid oxygen has a density of 1140 kg/m³ and is moderately cryogenic (freezing point: −219 °C, boiling point: −183 °C). Oxygen is found naturally in the air. For industrial applications it is obtained from air by fractional distillation. Liquid oxygen is a powerful oxidising agent: organic materials will burn rapidly and energetically in liquid oxygen, hence LOx is a common liquid oxidizer propellant for spacecraft rocket applications usually in combination with liquid hydrogen or kerosene. It was used in the very first rocket applications like the V2 missile and Redstone, R-7 Semyorka or Atlas boosters. LOX is useful in this role because it creates a high specific impulse. LOx was also used in some early ICBMs although more modern ICBMs do not use LOX because its cryogenic properties and need for regular replenishment to replace boiloff make it harder to maintain and launch quickly.
LOX also had extensive use in making oxyliquit explosives.
Liquid nitrogen has a significantly lower boiling point (77 K) than oxygen (90 K), and vessels containing liquid nitrogen can condense oxygen from air: when most of the nitrogen has evaporated from such a vessel there is a risk that liquid oxygen remaining can react violently with organic material. Conversely, liquid nitrogen can be oxygen-enriched by letting it stand in open air; atmospheric oxygen dissolves in it, while nitrogen evaporates preferentially.
See also
External links
- LOx enhanced combustion: Lighting a barbeque with liquid oxygen Do not try this yourself
- Dave Barry's comment on the above: Liquid oxygen can overcome balky charcoal
- Demonstration of the paramagnetism of LOx