And then he said there is a second term here, a contribution to the unequal sharing.

然后他说还有第二个条件，就是非平均共价的贡献。

麻省理工公开课 - 固态化学导论课程节选

And to measure the intensity of unequal sharing, we take the difference in electronegativity, which I am going to use the Greek symbol chi for.

要度量非平均的程度，我们考虑电负性的差异，我要用希腊语第22个字母chi来表示电负性。

麻省理工公开课 - 固态化学导论课程节选