And then this second term, if we go to the Periodic Table, 2 we will find that the value here for hydrogen is 2.2 98 and the value for fluorine is 3.98.

再算上第二个条件，翻看元素周期表，我们查处H，F电负性分别为2,2。2，3。

麻省理工公开课 - 固态化学导论课程节选