But he said the energy of an X-Y bond is going to be equal to the square root.

但他说ＸＹ键的键能,会等于ＸＸ键与ＹＹ键键能乘积的平方根。

麻省理工公开课 - 固态化学导论课程节选

So in the first case of this first bond here that I've put in a square, what type of a bond is this, is the sigma or pi?

在这第一个键里,我用方框把它标出来了，这个键是什么类型的，sigma还是π？

麻省理工公开课 - 化学原理课程节选