Chemistry of Phosphorus

As a member of the Nitrogen Family, Group 15 on the Periodic Table, Phosphorus has 5 valence shell electrons available for bonding. Its valence shell configuration is 3s²3p³. Phosphorus forms mostly covalent bonds. Any phosphorus rock can be used for the production of elemental phosphorus. Crushed phosphate rocks and sand (SiO2) react at 1700 K to give phosphorus oxide, P4O10:

P4O10 can be reduced by carbon:

The structure of P4 can be understood by thinking of electronic configuration (s² p³) of P in bond formation. Sharing three electrons with other P atoms gives rise to the 6 P−P bonds, leaving a lone pair occupying the 4th position in a distorted tetrahedron.

 When burned with insufficient oxygen, P4O6 is formed:

To each of the P−P bonds, an O atom is inserted. Burning phosphorus with excess oxygen results in the formation of P4O10 . An additional O atom is attached to the P directly:

Thus, the oxides P4O6 and P4O10 share interesting features. Oxides of phosphorus, P4O10 , dissolve in water to give phosphoric acid,

Phosphoric acid is a polyprotic acid, and it ionizes at three stages: