Editing Liquid hydrogen (section)

==History==
{{further|Timeline of low-temperature technology}}
[[File:Liquid_hydrogen_bubblechamber.jpg|thumb|Liquid hydrogen bubbles forming in two glass flasks at the [[Bevatron]] laboratory in 1955]]
[[File:Hydrogen Tank - GPN-2000-001458.jpg|thumb|A large hydrogen tank in a vacuum chamber at the [[Glenn Research Center]] in [[Brook Park, Ohio]], in 1967]]
[[Image:Linde-Wasserstofftank.JPG|thumb|A [[Linde AG]] tank for liquid hydrogen at the [[Museum Autovision]] in [[Altlußheim]], Germany, in 2008]]
[[File:DOT Hazardous Material Placard liquid hydrogen.jpg|thumb|Two [[United States Department of Transportation|U.S. Department of Transportation]] placards indicating the presence of [[hazardous materials]], which are used with liquid hydrogen]]
In 1885, [[Zygmunt Florenty Wróblewski]] published hydrogen's critical temperature as {{convert|33|K|C F}}; critical pressure, {{convert|13.3|atm|psi}}; and boiling point, {{convert|23|K|C F}}.

[[Hydrogen]] was liquefied by [[James Dewar]] in 1898 by using [[regenerative cooling]] and his invention, the [[vacuum flask]]. The first synthesis of the stable isomer form of liquid hydrogen, parahydrogen, was achieved by [[Paul Harteck]] and [[Karl Friedrich Bonhoeffer]] in 1929.