parahydrogen

[ par-uh-hahy-druh-juhn ]

noun

, Physics, Chemistry.

1. the form of molecular hydrogen in which the nuclei of the two hydrogen atoms contained in the molecule have spins in opposite directions.

parahydrogen

/ ˌpærəˈhaɪdrədʒən /

noun

1. chem the form of molecular hydrogen (constituting about 25 per cent of the total at normal temperatures) in which the nuclei of the two atoms in each molecule spin in opposite directions Compare orthohydrogen

Word History and Origins

Origin of parahydrogen¹

First recorded in 1925–30; para- ¹ + hydrogen

Example Sentences

Gary Green, director of the York Neuroimaging Centre at the University of York, UK, is working with parahydrogen, a 'hyperpolarized' molecule in which the proton spins are more aligned than in many other molecules, and which generates a strong signal during MRI.

From Nature

In 2009, Green and his colleagues showed that they could transfer spins from parahydrogen to an organic molecule without changing the latter's chemical structure — the first step towards preparing hyperpolarized drugs or other molecules that bind to receptors, and then track how these substances are taken up, or how they interact.

From Nature

Orthohydrogen and parahydrogen, two different kinds of hydrogen molecules having electrons revolving in different directions, discovered.

From Time Magazine Archive

That was proof that he had two different kinds of hydrogen, which he called orthohydrogen and parahydrogen.

From Time Magazine Archive

“Indeed,” he rambled on, “Treadmore babbled for Heaven knows how long on the relative occurrence of parahydrogen and orthohydrogen on Eisberg.”

From Project Gutenberg