The name of the compound P4O10 is tetraphosphorus decoxide. Because it has four phosphorus atoms, the prefix tetra is added to the name phosphorus. The deca prefix for 10 oxygen atoms is added to oxide, the name given for oxygen.
The molecules of P4O10, which have an empirical formula P2O5, are held together by van der Waals forces that are weak. But, P4O10 boils at a high temperature, 423 degrees Celsius. It can be prepared by burning phosphorus in enough oxygen. Because of its strong dehydration feature, P4O10 is used in the conversion of amides into nitriles. Its dessicating power is sufficient to convert various mineral acids, such as HNO3, to their anhydrides like N2O5.