Duden - Das Wörterbuch chemischer Fachausdrücke
Orthohelium
Or|tho|he|li|um [↑ "ortho-" (5) u. ↑ "Helium"] ↑ "Ortho-Para-Isomerie" (2).
Or|tho|he|li|um [↑ "ortho-" (5) u. ↑ "Helium"] ↑ "Ortho-Para-Isomerie" (2).