> Are those proposed, or already predicted composite atoms, or have they been already found? Not an expert, but following the Wikipedia links, some of them are

> Are those proposed, or already predicted composite atoms, or have they been already found? Not an expert, but following the Wikipedia links, some of them are real... Positronium was "experimentally discovered by Martin Deutsch at MIT in 1951" [0] Hypernucleus was "was discovered by Marian Danysz and Jerzy Pniewski in 1952 using the nuclear emulsion technique" [1] [0] https://en.wikipedia.org/wiki/Positronium https://en.wikipedia.org/wiki/Positronium [1] https://en.wikipedia.org/wiki/Hypernucleus https://en.wikipedia.org/wiki/Hypernucleus