This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Cryogenics . Each type of hydrogen molecule consists of hydrogen atoms spheres connected by covalent bond connecting bar Light arrows indicated direction of nuclear spin heavy arrows penetrating spheres show direction of spin axis In orthohydrogen the less stable type at lower temperatures the spin axes point in the same direction