1、This is resonance, this is a case of a resonance structure.

2、The results of bench test and road test show that the abnormal noise reduced greatly after the improvement and the Helmholtz resonance structure is better than the film-damping structure.

3、Charge-separated resonance structures do not contribute very much to the resonance hybrid of butadiene.

4、So this is a case where we have resonance structures, or we call this a resonance hybrid.

5、When we talk about resonance structures, the key word is that the electrons are delocalized.