光线的发射处越远，年龄越大，类星体的光谱会缺失，因为某些波长的光线会被中性氦及氦离子或带电粒子吸收。

Light emitted from farther away, and thus older, quasars lacked this wavelength, because the light was getting absorbed by neutral helium as well as helium with a single ion-or charged particle.

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中性氢辐射出离子化氢所没有的特有的21厘米波长。

Neutral hydrogen emits radiation on a characteristic 21cm wavelength, while ionised hydrogen does not.

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那么，按照相同的逻辑，我们所有的正离子，事实上，它们的半径都会缩小，与它们的中性母体相比。

So, by the same logic, that means that all of our positively charged ions are, in fact, going to be smaller in terms of radius, compared to their neutral parents.

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So we're going to feel a higher z effective in the case of the ion compared to the neutral atom.

因此，我们在离子中,会比在中性原子中感受到更高的有效核电量。

麻省理工公开课 - 化学原理课程节选

So, let's try another example here, and let's try a case now where instead of dealing with a neutral molecule we have an ion, so we have c n minus.

那么，让我们来试一下另外一个例子，这次不是一个中性原子,而是一个离子，氰离子。

麻省理工公开课 - 化学原理课程节选

It's possible to take the cation and anion and restore them to their neutral states.

我们可能得到阴阳离子,并把它们以电中性形式存在。

麻省理工公开课 - 固态化学导论课程节选