A dianion is an anion with a net charge of −2. While there exist many stable molecular dianions, such as Tetrafluoroberyllate| and , thus far no stable atomic dianion has been found: Electron shielding and other quantum mechanical effects tend to make the addition of another electron to an atomic anion unstable.
A dianion is an anion with a net charge of −2. While there exist many stable molecular dianions, such as {{chem2|BeF_{4}^{2-} }} and {{chem2|MgF_{4}^{2-} }}, thus far no stable atomic dianion has been found: Electron shielding and other quantum mechanical effects tend to make the addition of another electron to an atomic anion unstable.
The most heavily studied atomic dianion is H, usually as a short-lived resonance between an electron and a hydrogen ion. In 1976, its half-life was experimentally measured to be 23 ± 4 nanoseconds.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).