Para-hydrogen

Name:
Para-hydrogen
Detailed information:
Type of molecular hydrogen preferred for rocket fuels. Molecular hydrogen (H₂) exists in two varieties, ortho- and para-, named according to their nuclear spin types. Ortho-hydrogen molecules have a parallel spin, para- an antiparallel spin. By cooling to liquid air temperature and use of a ferric oxide gel catalyst, the normal equilibrium of 3 ortho- to 1 para- is displaced and para-hydrogen may be isolated. It is being produced with less than 5 ppm impurities.