We can write out what it is for any certain atom or ion x, X so it's just x plus an electron gives us x minus.

我们可以用，X，来表示一个任意的原子或离子，因此可以写成，X，加一个电子等于负一价的。

youdao

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。

youdao

The experiments were made possible by a novel, one-layer ion trap cooled to minus 269 C (minus 452 F) with a liquid helium bath.

实验利用了一种单层离子势阱，并将其浸在液氦浴中冷却到零下269摄氏度。

youdao

When you add this whole thing up, -411kJ/mol it gives you a net of minus 411 kilojoules per mole or about 4 eV per ion pair.

当你全部加上时，得到净能量,或者是4eV每个离子对。

麻省理工公开课 - 固态化学导论课程节选