When the storm ended, the crew of the Flying Cloud could see the very southern coast of South America -- a place called Tierra del Fuego.

VOA: special.2011.07.06

But, can you see that as you get really close together the negative electronic cloud surrounding the two ions start to sense one another.

然后当你真的让它们,离得很近时,这两个离子周围的负电子云能感应到对方。

麻省理工公开课 - 固态化学导论课程节选

So, what I'm showing in this picture here is just an electron cloud that you can see.

你们可以看到我现在展示的这张图是,一个电子云。

麻省理工公开课 - 化学原理课程节选