Allotropes of phosphorous
solid forms of the element phosphorus
Phosophorus is an element that exists in different forms, called allotropes. The most common of these are white or red solids.
- In white phosphorous four atoms form a tetrahedral structure. There are two known crystalline forms. Because phosphorous will spontaneously ignite when it comes in contact with oxygen, it needs to be stored in a liquid such as water. Usually it is a waxy solid. Because it is highly flammable, white phosphorous is used as a weapon.
- Heating white phosphorous to about 270 °C (518 °F) without air will give red phosphorous. Red-phosphorous is amorphic, and will no longer self-ignite when exposed to air. It is used as a fire retardant. When expsed to a little energy, red phosphorous can explode.
- Black phosphorous is the most stable form. It is obtained by exposing white phosoprous to a high pressure.
