Name: 分子性固体 (Molecular solids)
Uploaded: 2021-01-14T10:33:46.000Z
Duration: 8 min 13 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

- [Instructor] So let's talk a little bit

So those might be the positive ions right over there,

And the negative's attracted to the positive.

The positive's attracted to the negative.

And I'm just showing a two-dimensional version of it,

but it forms a three-dimensional lattice.

where you have metals that all contribute

some valence electrons to this sea of electrons.

very good at conducting electricity, malleable, et cetera.

Now what we're going to do is talk about what happens

So the nonmetals you can see in yellow right over here,

Now, of course, noble gases are also nonmetals,

So we're gonna talk about the reactive nonmetals.

Now, when we're talking about molecular solids,

we're talking about putting a bunch of these together.

So let's say putting a bunch of iodine molecules together,

at a sufficiently low temperature are sufficient

to hold together those molecules as a solid.

This right over here is a picture of solid iodine,

and the way it's made up is you have these iodine molecules.

Now, each of these iodine molecules are formed

by a covalent bond between two iodine atoms.

We talked about these London dispersion forces

inducing dipoles in neighboring molecules.

for a moment, you might have more electrons

And then that means that some of the electrons

on this end of this neighboring iodine molecule

might be repulsed by that negative charge,

inducing a dipole in a neighboring molecule,

and then they'll be attracted to each other.

And we've talked about that as London dispersion forces.

that can keep them all together as a solid.

I keep saying sufficiently low temperature

the covalent bonds hold together each of the molecules,

They tend to have relatively low melting points.

For example, solid iodine right over here

That's higher than the temperature at which water boils.

It would be quite uncomfortable for any of us

to be experiencing 113.7 degrees Celsius.

But this is relatively low when you talk about solids.

Think about the temperatures it takes to melt iron.

There you're talking about hundreds of degrees,

in certain solids, thousands of degrees Celsius.

molecular solids tend to have relatively low melting points.

Now, how good do you think they're going to be

Well, in order to be conductors of electricity,

somehow charge needs to move through the solid.

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分子性固体 (Molecular solids)

essentially

incredibly

bunch

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