Name: 鎳 - 視頻週期表 (Nickel - Periodic Table of Videos)
Uploaded: 2021-01-14T10:15:44.000Z
Duration: 13 min 45 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。

Nickel is element number 28 between Cobalt (27) and Copper (29)

Nickel has been known for a long time as an element or as a mixture with other metals

But it was only isolated as an element in

1751 by Axel Friedrich Cronstedt in Sweden.

To begin with it didn't have really much use and the big breakthrough for Nickel came in the 19th century

when it was discovered that if you added Nickel to Steel

Particularly armor plates for ships so that

your ship was stronger than the enemies and their shells couldn't penetrate

About the same time, a large deposit of Nickel or Nickel ore

was discovered in Sudbury in Ontario in Canada so that in some ways...

There are also now large deposits in Russia

But the Canadians have become so proud of Nickel

Axel Friedrich Cronstedt, his portrait is on the premier medal of the Canadian Institute of Chemistry

It is thought that the nickel deposit in Canada probably came with a meteorite from outer space,

because meteorites quite often have a very high Nickel content

and presumably in the very distant past a massive meteorite struck what is now Canada

You don't need a very large diameter meteorite to contain an awful lot of metal.

The big breakthrough in the refining of Nickel came in 1890

when the British chemist, Ludwig Mond, who was a major industrialist, had a problem in his chemical works

that some of the Nickel valves on his chemical plant were found to corrode - dissolve

And he discovered or his assistant Finker discovered

that this was caused by a reaction between Carbon Monoxide and Nickel.

In 1890 they published a key paper about the compound.

The compound is called Nickel Tetracarbonyl { Ni(Co)4 }

It consists of essential nickel atom surrounded by four Carbon Monoxide groups arranged in a tetrahedron.

What made this compound really unusual is that when you think about transition metals - Iron, Copper, Nickel,

you think of coloured salts which are solids all the time

Nickel Carbonyl was a liquid, it was colorless and it boils at 43° C (107.6° F)

So it was almost a gas at room temperature.

The important thing about Nickel carbonyl

is that you can distill it easily and if you heat it up it decomposes back into nickel and carbon monoxide

So it turned out to be a really good way of purifying Nickel ore

And Mond set up a company specifically to get nickel from the ores in Sudbury.

So he was reacting the ore with carbon monoxide which extracted out the nickel and in fact some of the iron -

both of these so-called carbonyl compounds

You can then separate them by distillation

Heat them up to decompose them and you get absolutely pure nickel and some iron as well.

It was then discovered that nickel was a very good catalyst for reacting organic compounds with hydrogen

And particularly it was discovered that you could hydrogenate vegetable oils, sort of cooking oils that you use.

And these oils have Carbon-Carbon double bonds.

If you react this with hydrogen, the melting point of the oils increases

And this is how you make margarine, by reacting vegetable oil with hydrogen and the Nickel is the Catalyst.

The hydrogen is absorbed onto the surface of Nickel the organic compound is also absorbed onto the surface

and when the molecules are held there, the hydrogen can transfer from the nickel onto the carbon of the double bond.

I was very keen to do a big experiment demonstration in this video,

and I wanted to do it with a material called Raney Nickel.

Murray Raney was an American chemist working on the hydrogenation of fats trying to make a better catalyst

and the problem with the catalyst is, because it is solid and the molecules are absorbing on the surface

the bigger the surface area within reason, the better the catalyst.

So he needed some way of dividing up the nickel

so it was in very small particles, so it had a very large surface area

And he hit on the idea of mixing molten aluminium and molten nickel -  these melted metals

And they mix when they are liquid, but when they solidify they separate

So you end up with a lump of aluminium with tiny bits of Nickel embedded in the solid

rather like currants or cherries in the cake

You can then put these mixed nickel aluminum pellets into sodium hydroxide

The sodium hydroxide dissolves the aluminium,

rather like we've done before with Coke cans

and they leave the nickel quite untouched

But they come out like removing the cherries from the cake

I had read that Raney nickel is Pyrophoric, it reacts with oxygen in the air and bursts into flames

So I went to talk to my colleagues in organic chemistry who use Raney nickel

and you buy it as a slurry so it's wet to avoid it bursting into flames.

So I got a bottle which looked a bit old, but I was assured was probably okay

And I persuaded Neil to pour it onto a filter paper

And so what I expected was that it would dry out

and then you would be left with this dried tiny particles of Nickel which would

absorb oxygen, start burning, heat up more and more and burst into spectacular flames

Unfortunately, it didn't. In fact when Neil eventually set fire to the filter paper...

I think that the air had got in and slowly dissolved in the water and reacted over a period of months

and oxidized the nickel so probably what we had was some form of nickel oxide

But they are all fairly black in color so you can't really tell what you've got

So I rushed off and found another professor who had a much fresher sample

and he told us we had to dry it on the hot plate

and he got quite worried, thought we'd used rather a lot of nickel.

the GoPro, the thermal camera, Brady standing there

And what this demonstrates, is that sometimes

what chemists tell you about reactions are not always what happens in the lab.

that if you're making margarine on a huge scale...

Tens of thousands of tons, and have got a huge amount of Raney nickel

then probably you can get quite a serious fire.

But we don't have that much Raney nickel, and we don't want a serious fire.

So, well, first of all let's look at some nickel