Phosphorus pentoxide

September 08, 2008
Image of Phosphorus pentoxide

Phosphorus pentoxide (empirical formula P2O5) is known to many laboratory workers as a powerful desiccant. It is manufactured by burning elemental phosphorus in a current of dry air. P2O5 exists in several crystalline and amorphous forms, the most common of which is the crystalline P4O10 shown. In the fertilizer industry, phosphorus concentration is expressed as weight percent P2O5 equivalent.

MOTW update: 
February 28, 2022

Phosphorus pentoxide1 (P4O10)  is a powerful drying agent that can also be used to remove the elements of water from organic and inorganic compounds.

P4O10 has also found use as a metal-free acid catalyst. In a recent example, Evgeny A. Mostovich and colleagues at Novosibirsk State University (Russia) used it to promote the cyclization of di[aryl(heteroaryl)methyl]malonic acids en route to fused, π-extended spiro[4.4]nonane-1,6-diones, which may have valuable optoelectronic applications.

1. CAS Reg. No. 16752-60-6.

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