All right, so the bonding order, you're correct, should be 2, if we subtract the number of bonding minus anti-bonding electrons and take that in 1/2.

好，你们是对的，键序为，如果我们用成键数,减去反键数除以2。

麻省理工公开课 - 化学原理课程节选

So for the bond order we want to take 1/2 of the total number of bonding electrons, so that's going to be 4 minus anti-bonding is 4, so we end up getting a bond order that's equal to 0.

键序等于1/2乘以,总的成键电子数，也就是4，减去反键电子数，也就是4。,所以最后得到键序为0。

麻省理工公开课 - 化学原理课程节选