phosphazenes

https://doi.org/10.1351/goldbook.P04551
Compounds containing a phosphorus–nitrogen double bond, i.e. derivatives of H3P=NH and HP=NH . A multiplicity of such bonds is present in various well-established chain, ring and @C00769@ compounds. E.g.
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Source:
PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1357 [Terms] [Paper]