And it turns out that when you constructively have two p orbitals interfere, and when I say constructively, I mean they're both either positive or they're both the negative lobes, that's when you got bonding.

当两个ｐ轨道,相长干涉时，我说的相干相长，意思就是说它们要么都是,正的叶瓣要么都是负的叶瓣，这时就能成键。

麻省理工公开课 - 化学原理课程节选

So here, I'm going to have delta H, is just the sum for all the products of delta heat of formation right? Here I'm going to put together all the products. So this is a positive heat of formation.

所以这里△H就是所有生成物的,生成热的和,对吧？这里,我要把元素组合成所有这些,生成物，所以这里是正的生成热。

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