It's 109 . 5 is what we would expect for methane because it's tetravalent, but here we're just seeing something that's divalent, and they're both in p orbitals that are perpendicular to each other.

因为甲烷是四价的，我们预测是109。,但这里我们，看到的是二价的，它们都在。

麻省理工公开课 - 化学原理课程节选

So this should immediately look like a problem because we know, in fact, that methane is tetravalent, and this is telling us it's only divalent.

显然这看起来是一个问题,因为我们知道实际上，甲烷是四价的，而这告诉我们它仅仅是二价的。

麻省理工公开课 - 化学原理课程节选