If these bonds were all completely of equal distance apart, whether is was a lone pair or bonding electrons, 5° the angles would be 109 . 5 degrees.

如果不管它是孤对，还是成键，它们等距分开的话，键角是109。

麻省理工公开课 - 化学原理课程节选

But because there's this lone pair here, it's pushing down on the other bonds, 5° so we end up with an angle of less than 109 . 5 degrees.

但因为这里有孤对，它会把其它键向下压，所以键角会小于109。

麻省理工公开课 - 化学原理课程节选

If you do look down at the Periodic Table and get above 109, Uun Uuu Uub you will see these strange notations here, Uun,Uuu,Uub What is all of this?

如果你看周期表的下面部分,到109号，你会看到这些奇怪的符号,这些是什么呢？

麻省理工公开课 - 固态化学导论课程节选

You can do that on email, you can do that in my office, which is downstairs on the first floor of this building, in LC-109.

发邮件，来办公室找我，我的办公室在这栋楼的1层，LC109室。

耶鲁公开课 - 现代诗歌课程节选

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

And it turns out that it's actually less than 109 . 5, because those lone pairs are pushing the bonds even further away.

所以结果是它要小于109。,因为孤对会把成键推向更远。

麻省理工公开课 - 化学原理课程节选

So, we've achieved the angle that we observed, which is a 109 . 5.

我们得到了我们观察到的角度，是109。5。

麻省理工公开课 - 化学原理课程节选

So what we see is on ammonia here, 107 we know that it's less than a 109 . 5, it's actually 107, so it's less than a 109 . 5, because of that lone pair pushing down in the bonding electrons.

我们看到在氨分子里，我们知道它比１０９．５要小，它是，所以比109。5要小，因为孤对会把成键电子向下推。

麻省理工公开课 - 化学原理课程节选

We have two lone pairs, so if we thought about what the bonds were everywhere, 5° it would be 109 . 5, but it's bent because we're only looking at the bonds, we're not counting the Lewis structures in naming our geometry, but they do affect the angles.

我们有两个孤对，所以如果我们考虑它会成怎样的键时，应该成109。,但它是折线型，因为我们只考虑成键，在几何形状里不考虑Lewis结构，但它会影响角度。

麻省理工公开课 - 化学原理课程节选

So if we still have an angle of a 109 . 5 degrees, and again, we still have four unpaired electrons available for bonding, we can make one of those bonds with another s p 3 hybridized carbon, so we're going to make up one pair here.

如果键角仍然是109。,同样，我们还有4个未配对的电子可以用来成键，我们可以用其中的一个,和另外一个sp3杂化碳原子成键，这样我们可以组成一对。

麻省理工公开课 - 化学原理课程节选