So we could think about comparing the potassium ion to a sodium ion. They have the same charge of plus one.

我们可以想象比较一下钾离子,与钠离子，它们都同样带有正一价的电荷。

麻省理工公开课 - 化学原理课程节选

It's 109 . 5 is what we would expect for methane because it's tetravalent, but here we're just seeing something that's divalent, and they're both in p orbitals that are perpendicular to each other.

因为甲烷是四价的，我们预测是109。,但这里我们，看到的是二价的，它们都在。

麻省理工公开课 - 化学原理课程节选

And this is just a picture showing some of these sizes with their parent. So, for example, a lithium here, you can see how lithium plus is smaller than the actual lithium atom in its neutral state.

这是一张对比图,展示某些离子与它们的母体，比如，这里是锂，大家可以看到正一价锂离子是多么的小,与中性锂原子相比。

麻省理工公开课 - 化学原理课程节选