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View Full Version : Liquid Metallic Hydrogen-What does it Look Like?



Mr. Milton Banana
2004-Jan-26, 11:32 PM
Jupiter and Saturn's "surfaces" are basically massive oceans of liquid hydrogen. My understanding is that liquid hydrogen is colorless.

In each planet, enormous pressures halfway in change the hydrogen to liquid metallic hydrogen.

What would that look like? Anyone want to take a guess? And what would be its properties?

8)

Edymnion
2004-Jan-27, 01:07 AM
We're not even entirely sure hydrogen CAN become a solid...
And technically, Hydrogen isn't a metal. It is classified as being non-metallic. Alkaline Metals applies only to Lithium and below. This is why Hydrogen is classically seperated from the rest of the Periodic Table, because it doesn't really fit with anything else we know.

Aka, it could be literally anything if/when it becomes a solid.

Coragyps
2004-Jan-27, 03:55 AM
I'm guessing, OK? Even though I'm a chemist by training and profession, I'm no expert on metallic hydrogen.....
But if you had optics that could see inside a pressure cell strong enough to confine metallic hydrogen, it would look like mercury (if liquid) or silver (if solid.) A part of the reason that metals like those look, ... well, metallic...is that they consist of a bunch of ions sitting in a sea of swarming electrons, which (somehow....remember, chemist, not physicist) bounce photons off in a shiny, metallic sort of way. As for properties, likely very similar to molten sodium or lithium: good thermal and electrical conductor, maybe very "runny" if liquid. Really, really flammable near oxygen. My $0.02, anyway.

Edymnion
2004-Jan-27, 04:14 AM
http://www-phys.llnl.gov/H_Div/GG/metalhydrofact.html
Apparently we HAVE succeeded in making solid hydrogen. Still hasn't been determined if its actually a metal or not.

http://www.webelements.com/webelements/elements/text/H/key.html
Lists Hydrogen as being Non-Metallic.

Mr. Milton Banana
2004-Jan-27, 05:04 AM
http://www-phys.llnl.gov/H_Div/GG/metalhydrofact.html
Apparently we HAVE succeeded in making solid hydrogen. Still hasn't been determined if its actually a metal or not.

http://www.webelements.com/webelements/elements/text/H/key.html
Lists Hydrogen as being Non-Metallic.

My understanding, if I'm correct, is that at those intense pressures, hydrogen develops *some* properties of metal-so it's not a true metal-more of a pseudo-metal.

Maybe those with bigger brains than mine can help out?

:D

Taibak
2004-Jan-27, 06:29 AM
Yeah, I've definitely read that under *HUGE* pressures - we're talking the cores of Jupiter and Saturn here - Hydrogen starts acting like a metal. I'm not sure if it's been produced on Earth yet, or if its purely theoretical based on observations of the planets.

And if it is a metal, the safe money is on it being grey and shiny. :wink:

Swift
2004-Jan-27, 01:59 PM
Solid hydrogen has been made in diamond anvil cells. To my knowledge, no one has made metallic hydrogen. I would agree with others that it should be metallic - good conductor of electricity and heat, etc.

This phase diagram is in temperature and density:
http://militzer.gl.ciw.edu/diss/node5.html

I also found this talk which has a fair amount of phase diagram info. The main subject of the talk was actually speculation on using metallic hydrogen as rocket fuel!
http://www.spacetransportation.com/ast/2003_prop_workshop/pres-pdf/1b_silve.pdf

I suspect that Jupiter and Saturn don't have anything like we would call a surface - i.e. a sharp transition from gas to liquid or solid. It may be a gradual densification. Not all phase diagrams have sharp boundaries. We are probably also not dealing with pure hydrogen in their atmospheres.

Alex W.
2004-Jan-27, 10:53 PM
Doesn't astrophysics consider everything past Helium to be a metal anyway? :wink:

You crazy, crazy astro-men!


Anyway, serious time. You don't need a metallic material to get a shiny effect (there are some great semiconductor polymers that are shiny), so it might be possible to get the inverse- something metallic that doesn't look shiny.

I think. I gassed myself with HCl fumes on Monday morning and I've been a bit off-kilter since.

Swift
2004-Jan-27, 11:04 PM
You don't need a metallic material to get a shiny effect (there are some great semiconductor polymers that are shiny), so it might be possible to get the inverse- something metallic that doesn't look shiny.

But to be metallic, it means that the difference between the valence band and the conduction band is very low (actually zero in real metals). A very low bandgap semiconductor would appear metallic if, for example the bandgap energy was in the IR and you looked in the visible.

I might be wrong, but I can't think of a mechanism where something would be shiny and not be a metal, with one exception (that has nothing I think to do with Jupiter). A very finely divided metalic powder does not necessarily look metallic, it often looks black. I suspect this is because it can absorb the visible light (tiny bandgap), though I'm not competely sure why it doesn't look shiny, maybe something to do with the morphology of the surface.

Sorry about the HCl.

Madcat
2004-Jan-28, 12:09 AM
Hey, give us the tale of gore! :)

I burned myself on a ring stand monday. I figured the wing nut that was holding the thing in place wouldn't get hot, and I figured wrong. My thumb looks really cool now. :oops:

daver
2004-Jan-28, 01:00 AM
I think. I gassed myself with HCl fumes on Monday morning and I've been a bit off-kilter since.
Our chemistry professor did that a few times--he'd fill a balloon with H and Cl and flash it with a camera flash to demonstrate a photochemical reaction. He talked a bit funny for the next few minutes. I expect he just eyeballed it, so some days he'd get a bit extra H2, others a bit extra Cl2. He was saying that one year the lecture hall was in a different building than the chem building--he filled the balloon in the chem building, hid the balloon inside his raincoat, and scurried over to the lecture hall (looking a bit like a flasher, as it was sunny and warm out). Fairly predictable results (hey, if everything went ok it wouldn't make a good story).

Wingnut Ninja
2004-Jan-28, 04:24 AM
I figured the wing nut that was holding the thing in place wouldn't get hot, and I figured wrong. My thumb looks really cool now. :oops:

Hey, sorry about that. My bad.

Alex W.
2004-Jan-28, 03:34 PM
In my case I dumpted about 10ml of thionyl sulphate into the chlorinated wastes bottle instead of the thionyl sulphate bottle.

Cue hydrolysis and a load of HCl. Whoomp!

I also recrystallised about a tenth of my product material on my hands today, through several small spillages. And there's a yellow stain on my finger that refuses to go away.

C'est la vie! :D

Thanks for the metallic shininess explaination there, Swift!

Kaptain K
2004-Jan-28, 07:19 PM
My chemistry professor got his nickname (Kaboom) when his reference material was off by a factor of 10 on the solubility of azoic acid. He wound up with a 2mm layer of it on top of the solvent. He wasn't hurt since the glassware was pulverized (no large shards), but the explosion was heard throughout the 6 story building. :o

daver
2004-Jan-28, 09:53 PM
This was the same prof who advised us never to work in a glass-roofed chem lab (fortunately, when he did there was enough room under the lab bench to protect him from what was left of the roof).

Alex W.
2004-Jan-28, 10:52 PM
Great googley moogley. Sounds like a lot of fun. It's a pity that safety rules are so strict these days, you've got to count on your fellow students to do silly things and cause calamity.

One of our Prof.s told us about an experiment that combined two great errors. The first was that someone poured an organic solvent (an ether, IIRC) into the sink, which because of the plumbing, went around the room filling all the sinks with vapour.

Someone then dumped a bit of sodium down one of the sinks. Cue a fireball racing around the room. Shame it was before I was born, it would've been quite a spectacle.