3 Lithium---锂

00:01 so it’s Lithium. Lithium is at top of alkali metals, lightest of all of them. Very reactive, we use it a lot in organic chemistry to active carbon-carbon bond formation. But you see here, it’s a very dark-color metal. It is actually very shiny if you cut it fresh. But it reacts with Nitrogen in the air to form Lithium-Nitrogen very very quickly.
这是锂。锂是最轻的碱金属。非常活跃。它通常被使用于有机化学中碳碳合成。看，它的颜色很暗。实际上切开它会是亮泽的。但是它与空气中的氮气发生反应，迅速产生氮化锂。

00:23 So Lithium is the lightest metal. It’s a very light element, it will float on water. Of course it will react with water as well.
锂是最轻的金属，它是一种很轻的元素，能够浮于水面。当然，它也能与水反应。

00:33 so we take a small sample, and we are gonna see what happens when it reacts with water.
我们拿一块样品，观察它与水的反应。

00:39 it has had a number of quite important applications for the last few years. Some of you will know Lithium is used in shooting, what is now called Bipolar disorder or manic depression.
过去几年出现了一些非常重要的锂的应用。你们有些人会知道锂应用于摄影，现在用于双相障碍或者称为躁郁症。

00:54 the Lithium is self-store under oil to stop reacting with the air and also with water. So we’ll just clean the oil before it pop into the sample of water.
锂必须储存于煤油，以防止与空气或水反应。我们把它放进水之前要清理干净粘上的煤油。

01:06 in fact, though I am not a great expert in pop-songs, there is at least one pop song call Lithium based on this.
虽然我不是流行歌曲的专家，但我知道有一首流行曲叫“锂”，就是基于它的。

01:14 so here we have the dry lithium, which you can see. I am just drop the metal into the water and see what happens. It fades around a little bit. So you see the lithium reacts quite rapidly with the water, and you see hydrogen gas been involved. And if we catch the hydrogen gas in a beaker, in a test-tube, we can light it and burn it.
现在你们看到干的锂金属。我把金属放进水里看发生什么。它渐渐减少。我们看到锂于水的反应非常迅速。氢气也产生了。如果我们用烧杯或者试管捕捉氢气，我们就可以点燃它。

01: 39 but Lithium is very reactive. One of my colleague said if we had a fire with Lithium, you will never put it out.
锂是非常活跃的，我的一个同事说过，如果有一场锂的火灾，将会永远都不能扑灭。

01:54 you can see fresh color in there, nice and shiny. But as it reacts with Nitrogen, it forms Lithium-Nitrogen which is black.
你看看里面的光泽，很亮。但是当它与氮气反应，就会形成黑色的氮化锂。

02:00 it reacts with Nitrogen in the air which is one of the metals that react with Nitrogen spontaneously. So that, if you had a container of Lithium, which is been exposed to air, it tends to smell of ammonia because it is reacted with Nitrogen, and then the water in the air reacts with the sole that is formed, and you got to smell of ammonia so it smells a bit like thirty nappies.
锂与空气中的氮气发生反应，它是在常温常态下能与氮气发生反应的金属之一。若有一容器的锂金属暴露于空气中，就会有一阵氨水的味道。因为锂与氮气发生反应，空气中的水再与产生的晶体产生反应，产生氨就会有一种氨水的味道，因为它闻起来就像肮脏的容器。