The stoichiometric oxidation of white phosphorus yields phosphorous trioxide, Equation 1.
Several structural forms of phosphorous trioxide are known, but P4O6 is a stable molecule structure (Figure 1), while the rest are polymers.
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The stoichiometric oxidation of white phosphorus yields phosphorous trioxide, Equation 1.
Several structural forms of phosphorous trioxide are known, but P4O6 is a stable molecule structure (Figure 1), while the rest are polymers.
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The reaction of white phosphorus with excess oxygen (or the oxidation of phosphorous trioxide) yields phosphorous pentoxide, Equation 2.
The structure of hexagonal phosphorous pentoxide is actually that of the dimeric form, P4O10, and is based upon the structure of P4O6, but with P=O units instead of lone pairs (Figure 2). The structure is maintained in the vapor phase; however, other crystalline and glassy forms comprise of a sheet-like structure (Figure 3).
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Phosphorous pentoxide is an excellent drying agent below 100 °C. It reacts with water to form various phosphoric acids, and it will extract water from other ‘drying agents’, e.g., Equation 3 and Equation 4. Phosphorous pentoxide will dehydrate amides to give nitriles, Equation 5.