What are the major allotropes of phosphorus?

Phosphorus exists in several solid modifications known as allotropes. The three major allotropes are white, red, and black phosphorus.1

• White Phosphorus: This is a metastable, highly reactive, and toxic form consisting of tetrahedral $P_4$ molecules. Due to its high reactivity, it can spontaneously ignite in air and must be stored under water or an inert liquid.1
• Red Phosphorus: Formed by heating white phosphorus, this polymeric substance is relatively inert and insoluble. It is commonly used in the manufacturing of safety matches.1
• Black Phosphorus: Produced under high temperatures and pressures, this flaky, crystalline form somewhat resembles graphite. It is the most stable of the three allotropes and is capable of conducting electricity.1

While these are the primary forms, phosphorus can exist in up to 10 different solid modifications under ordinary conditions.1