NO3 Partial Double Bond [ENDORSED]

[Mannat Sukhija 1E]

In the example Lavelle did in class with the resonance structure of NO3, why would the partial double bond have a length of 1.5 bonds and not 1.33 since there are 3 N-O bonds that the extra bond length must be divided between?

[Nathan_Summers_2B]

As I remember, he did say that each bond would be the length of 1.33 bonds, though it might have been as an aside in response to a question, so it could have been pretty easy to miss. I may be remembering incorrectly, but I'm fairly certain that I'm not. However, since double bonds are shorter than single bonds, using "1.33 bonds" or even "1.5 bonds" is misleading as it implies that they're both longer than single bonds, when the opposite is true, so it's not the best notation to use when talking about this.

[Chem_Mod]

1.33 is correct