View article

According to generał chemistry textbooks, three basic allo-tropic modifications of elemental phosphorus exist, namely, white, red, and black phosphorus, which differ considerably in their chemical and physical properties. When white phospho-rus is heated or exposed to radiation, it is transformed to amorphous red phosphorus. The structure of red phosphorus is considered to be a polymeric network of different building units, which are well-known from various compounds con-taining polymeric phosphorus structures"" While this net-work features only short or intermediate range order, further heating or irradiation leads to crystallization. Different crystalline allotropes were reported to form in this way, for example, red phosphorus IV and red phosphorus V, which were characterized by X-ray powder diffraction." Already in 1865 Hittorf found that phosphorus can also be crystallized from a melt of lead, giving red-to …