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Liquid helium is a physical state of helium at very low temperatures at standard atmospheric pressures.Liquid helium may show superfluidity.. At standard pressure, the chemical element helium exists in a liquid form only at the extremely low temperature of −269 °C (−452.20 °F; 4.15 K).
Solid helium has a density of 0.214 ... can achieve about 0.2 kelvin in a helium-3 refrigerator. ... its extremely low temperatures can result in cold burns, ...
However, Kamerlingh Onnes, his rival, was the first to liquefy helium, in 1908, using several precooling stages and the Hampson–Linde cycle. He lowered the temperature to the boiling point of helium −269 °C (−452.20 °F; 4.15 K). By reducing the pressure of the liquid helium, he achieved an even lower temperature, near 1.5 K.
The combination of helium’s extremely low molecular weight and weak interatomic reactions yield interesting properties when helium is cooled below its critical temperature of 5.2 K to form a liquid. Even at absolute zero (0K), helium does not condense to form a solid under ambient pressure.
Nitrogen is a liquid under −195.8 °C (77.3 K).. In physics, cryogenics is the production and behaviour of materials at very low temperatures.. The 13th International Institute of Refrigeration's (IIR) International Congress of Refrigeration (held in Washington, DC in 1971) endorsed a universal definition of "cryogenics" and "cryogenic" by accepting a threshold of 120 K (−153 °C) to ...
Helium also has a very low boiling point (-268.9°C or -452°F), allowing it to remain a gas even in super-cold environments, an important feature because many rocket fuels are stored in that ...
2.5 mK, Fermi melting point of helium-3; 60 mK adiabatic demagnetization of paramagnetic molecules; 300 mK in evaporative cooling of helium-3; 700 mK, helium-3/helium-4 mixtures begin phase separation; 950 mK, melting point of helium at 2.5 megapascals of pressure. All 118 elements are solid at or below this temperature. microwave excitations
Values are in kelvin K and degrees Celsius °C, rounded For the equivalent in degrees Fahrenheit °F, see: Boiling points of the elements (data page) Some values are predictions