Inorganic phosphate rock (Calcium Phosphate rock), which is partially made of Apatite (an impure tri-calcium phosphate mineral), is today the chief commercial source of this element.
Common allotropes are White and Red phosphorus.
Another form, Scarlet Phosphorus, is obtained by allowing a solution of white phosphorus in carbon disulfide to evaporate in sunlight.
Black Phosphorus is obtained by heating white phosphorus under high pressure (12,000 standard atmosphere). In appearance, properties and structure, it resembles graphite, being black and slaky.
Another allotrope is diphosphorus, it contains a phosphorus dimer as a structural unit and is highly reactive.
White phosphorus is the least stable, the most reactive, the most volatile, the least dense, and the most toxic of the allotropes.
White phosphorus is highly flammable and pyrophoric (self-igniting) upon contact with air and is toxic.
Red phosphorus may be formed by heating white phosphorus to 250°C or by exposing white phosphorus to sunlight. Phosphorus after this treatment is amorphous. Upon further heating, this material crystallises.
After prolonged heating or storage, the color darken; the resulting product is more stable and does not spontaneously ignite in air.
Violet phosphorus is a form that can be produced by day-long annealing of red phosphorus above 550°C.
Black phosphorus is the least reactive allotrope and thermodynamically stable form below 550°C. High pressures are usually required to produce black phosphorus, but can be produced at ambient conditions using metal salts as catalysts.
Phosphine is produced by hydrolysis of Calcium Phosphide (Ca3P2). Unlike ammonia, phosphine is oxidized by air.
Phosphides arise by reaction of metal with Red Phosphorus.
