How is black phosphorus produced?

Black phosphorus is produced by converting other forms of phosphorus under specific conditions. It can be formed at high temperatures and pressures. Alternatively, it can be prepared at ordinary pressures and a temperature of approximately 200 °C (390 °F) through the use of a catalyst.1

This flaky, crystalline allotrope is considered the most stable form of the element, though its preparation is relatively difficult compared to other modifications. Unlike the highly reactive white phosphorus, black phosphorus is relatively inert and possesses the ability to conduct electricity.1