Phosphorus pentoxide is a phosphorous oxide. Phosphorus pentoxide is used as a strong drying and dehydrating agent. Many reactions that require the removal of a water molecule can utilize P2O5 such as the dehydration of amides to nitriles. It is primarily used in making optical glass and heat-insulating glass. In addition, phosphorus pentoxide is a key ingredient to produce pharmaceuticals and pesticides in the pharma and agricultural industry.