So what we'll have here is a trigonal planar case, and you can see that we only have three electrons that are set for bonding, so we'll add three hydrogens, and for b h 3, we'll get a stable structure here.

让电子劲量远离的时候，不用考虑它,这个例子是平面三角形，你可以看到，只有3个电子可以成键。

麻省理工公开课 - 化学原理课程节选

So if you picture, for example, b h 3, it's going to look like this.

如何使键劲量相互远离，我们会有平面三角形的情形，如果你想象。

麻省理工公开课 - 化学原理课程节选