Borromean Nucleus (image) American Physical Society Share Print E-Mail Caption Carbon-22 is now the heaviest observed Borromean nucleus. Borromean nuclei are named after the rings from the 15th century crest of the Borromeo family from Northern Italy. The rings are connected in such a way that the cutting of one ring results in the separation of all three. (Left) Marble representation of the Borromean rings, used as an emblem of Lorenzo de Medici in San Pancrazio, Florence. (Right) Schematic structure of 22C showing the two halo neutrons around a core. Removing any one element makes the entire structure unstable. Credit APS Physics Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.