Chemistry:Dianion

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Short description: Divalent negative ion

A dianion is an anion with a net charge of −2. While there exist many stable molecular dianions, such as Template:Format ion formula and Template:Format ion formula,[1] 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.[2]

The most heavily studied atomic dianion is H2−, usually as a short-lived resonance between an electron and a hydrogen ion.[2] In 1976, its half-life was experimentally measured to be 23 ± 4 nanoseconds.[3]

In the field of physiology, molecular dianions play an important roles, such as the monohydrogen phosphate ([HPO4]2−), present at a concentration of around 1 mM in the blood and in cells, where it plays a role in pH buffering.[4]

See also

References

  1. Middleton, Roy; Klein, Jeff (1999-11-01). "Experimental verification of the existence of the gas-phase dianions BeF42− and MgF42−". Physical Review A 60 (5): 3515–3521. doi:10.1103/PhysRevA.60.3515. https://link.aps.org/doi/10.1103/PhysRevA.60.3515. 
  2. 2.0 2.1 Andersen, T. (2004-05-01). "Atomic negative ions: structure, dynamics and collisions" (in en). Physics Reports 394 (4): 208–209. doi:10.1016/j.physrep.2004.01.001. ISSN 0370-1573. https://www.sciencedirect.com/science/article/pii/S0370157304000316. 
  3. "Double-negative hydrogen ion found" (in en). Chemical & Engineering News Archive 54 (7): 8. 1976-02-16. doi:10.1021/cen-v054n007.p008. ISSN 0009-2347. https://pubs.acs.org/doi/10.1021/cen-v054n007.p008. 
  4. Wadsworth, Rl; Siddiqui, S (September 2016). "Phosphate homeostasis in critical care". BJA Education 16 (9): 305–309. doi:10.1093/bjaed/mkw033.