parahydrogen

American  

[par-uh-hahy-druh-juhn] / ˌpær əˈhaɪ drə dʒən /

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.

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parahydrogen British  

/ 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

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Etymology

Origin of parahydrogen

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

Example Sentences

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

From Time Magazine Archive

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

From Time Magazine Archive

If they are oriented in opposite directions, it is parahydrogen.

From Unwise Child by Garrett, Randall

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

From Unwise Child by Garrett, Randall