Allotropes of Phosphorus - Black Phosphorus

Black phosphorus is the thermodynamically stable form of phosphorus at room temperature and pressure. It is obtained by heating white phosphorus under high pressures (12,000 atmospheres). In appearance, properties and structure it is very like graphite, being black and flaky, a conductor of electricity, and having puckered sheets of linked atoms.

Black phosphorus has an orthorhombic structure and is the least reactive allotrope: a result of its lattice of interlinked six-membered rings. Each atom is bonded to three other atoms. A recent synthesis of black phosphorus using metal salts as catalysts has been reported.

One of the forms of red/black phosphorus is a cubic solid.