Bond Orbitals and Bond Energy in Elementary Phosphorus

Abstract

A discussion of the relative stability of the P₄ molecule and black phosphorus is carried out, with use of hybrid spd bond orbitals. The amount of strain in the P₄ molecule, in which the bond angles are 60°, is calculated to be 22.8 kcal mole⁻¹. This value is shown to be compatible with thermochemical data; it corresponds to the value 51.3 kcal mole⁻¹ for the bond energy of the normal P–P bond. A structure is proposed for red phosphorus and other allotropic forms of the element, and some of their properties are discussed in relation to their structure.