Also known as Pn, antiprotonic hydrogen, proton-antiproton atom
thumb|An illustration of the protonium atom.
~3 min read
thumb|An illustration of the protonium atom.
Protonium, also known as antiprotonic hydrogen, is a type of exotic atom in which a proton (symbol: p) and an antiproton (symbol: ) are bound to each other.
via Wikidata sitelinks · CC0
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).