If we want to talk about two hydrogen atoms, then we just need to double that, so that's going to be negative 2 6 2 4 kilojoules per mole that we're talking about in terms of a single hydrogen atom.

而要讨论两个氢原子，我们只需要把它乘以二，因此应该是负的，2624，千焦每摩尔,这就是单个的氢原子的情况。

麻省理工公开课 - 化学原理课程节选

In contrast, if we talk about a double bond, what we're now talking about is having both a sigma bond and also one pi bond. And I apologize, I intended to set this up right before class, but that didn't happen today.

相反，如果我们讨论一个双键，我们现在讨论的是,一个sigma键和π键，抱歉，我应该在课前就把这个装好的，今天没装好。

麻省理工公开课 - 化学原理课程节选