It is an essential component of living systems and is found in nervous tissue, bones and cell protoplasm. White phosphorus has two modifications.
Ordinary phosphorus is a waxy white solid.
When pure, it is colourless and transparent. It is insoluble in water, but soluble in carbon disulphide. When exposed to sunlight, or when heated in its own vapour to 250 C, it is converted to the red variety. This form does not ignite spontaneously and it is a little less dangerous than white phosphorus. Both values are quoted on the Pauling scale.