It is the most common variety of phosphorus and is obtained by heating phosphorite rock or bone ash.

Structure:
The molecular structure of white phosphorus suggests that it is tetra atomic. It consists of discrete P₄ molecules. In P₄ molecule, each phosphorus atom is linked to three other P atoms. Each atom is at one apex of a pyramid. In P₄ molecule, the P–P–P angles are 60°. The lower value of bond angle indicates considerable strain and thus the molecule should be reactive. Different P₄ molecules are held together by weak van der Waal's forces.

Above 800°C, it dissociates into P₂ molecules, at 1700°C, its formula is P₂.

Physical properties of White Phosphorus:
It is a soft waxy solid (density 1.8 at 298K) with garlic odor and can be cut with a knife.

When freshly prepared, it is nearly colorless but acquires a pale lemon yellow color on standing due to the formation of the film of the red form on the surface. Therefore, also called yellow phosphorus.

• It is not soluble in water but is soluble in carbon disulphide.
• It is stored under water, due to its low ignition temperature(308 K). In absence of air, it boils at 553.15K
• It is poisonous in nature, in contact with air white phosphorus undergoes slow combustion and glows in dark. This property of glowing is known as phosphorescence. The main product of this slow combustion is phosphorus trioxide.

Chemical properties of White Phosphorus:
Combustion:Due to its low ignition temperature, white phosphorus

Action with NaOH: White phosphorus dissolves in caustic soda on boiling in an inert atmosphere and liberates phosphine.

Action with metals: Forms respective phosphides.

White phosphorus reacts with all the halogens at room temperature to form phosphorus trihalides.

Reaction with halogens
White phosphorus reduces concentrated H₂SO₄ to SO₂ and concentrated HNO₃ to NO₂