Form of the helium atom in which the spins of the two electrons are parallel.(noun)
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Use "orthohelium" in a sentence
"In orthohelium, on the other hand, the tracks of the two electrons lie in the same plane, the one being circular, while the other is elliptical."
"It occurs in two different modifications: one is called parhelium, and is the more stable, and the other is called orthohelium - these were supposed at first to be two different substances."