The Phosphorus-Nitrogen Linkage

Bond energy considerations (Chapter 3.4) indicate that in most compounds P-N should be a little stronger than P-C or N-N, and comparable with P=P. Similarly, P=N should generally be stronger than P=P but weaker than C=C or N=N. The P N bond is probably the strongest triple bond formed between two different pnictide elements. 

The P-N bond shows varying degrees of jt-bonding in different compounds and these bonds can be expected to be associated with a range of strengths and stabilities. There are two types of P=N linkages dn (P)-pn (N) and pn (P)-pn (N) (Chapter 3.4). 

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