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Diphosphorus



    Diphosphorus, P2, is the diatomic form of phosphorus. Unlike its nitrogen group neighbour nitrogen which forms a stable N2 molecule with a nitrogen to nitrogen triple bond, phosphorus prefers a tetrahedral form P4 because P-P pi-bonds are high in energy. Diphosphorus is therefore very reactive with a bond dissociation energy (117 kcal/mol or 490 kJ/mol) half that of dinitrogen.

Additional recommended knowledge

Traditionally diphosphorus can be generated by heating white phosphorus at 1100 kelvins. The compound attracted attention in 2006 when a new method for its synthesis at milder temperatures emerged [1].

This method is a variation on nitrogen expulsion in azides with formation of a nitrene. The synthesis of the diphosphorus precursor consists of reacting a terminal niobium phosphide with a chloroiminophosphane:

Heating this compound at 50 °C in 1,3-cyclohexadiene serving as a solvent and as a trapping reagent, expulses diphosphorus which reactive as it is forms a double Diels-Alder adduct and the niobium imido compound:

The same imido compound also forms when the thermolysis is performed in toluene but then the fate of diphosphorus in unknown.

References

  1. ^ Triple-Bond Reactivity of Diphosphorus Molecules Nicholas A. Piro, Joshua S. Figueroa, Jessica T. McKellar, Christopher C. Cummins Science 1 September 2006:Vol. 313. no. 5791, pp. 1276 - 1279 10.1126/science.1129630
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Diphosphorus". A list of authors is available in Wikipedia.
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