Cyclic mono- and diphosphazenes

Methods of synthesis of 5- and 6-membered heterocyclanes with one or two endocyclic P=N bonds (cyclomono- and cyclodi-phosphazenes) have been considered. Types of reaction common to acyclic analogues and specific types of reaction have been separated. The change of electronic structure and geometry of the P=N bond on changing from linear to cyclic phosphazenes are clearly displayed in the special features of their chemical behaviour.
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