Sciencemadness Discussion Board

High Pressures

DraconicAcid - 20-12-2013 at 22:00

http://www.sciencedaily.com/releases/2013/12/131219142138.ht...

Apparently, at a few thousand atmospheres, one can make compounds like Na3Cl and NaCl3. Cool.

Bot0nist - 20-12-2013 at 22:18

That is really cool. I recently saw a bit on tv that talked about how hydrogen will form a metallic allotrope I guess is the word, using very high pressures and temperatures with lasers of some form. Ill search around for a link.



[Edited on 21-12-2013 by Bot0nist]

blogfast25 - 21-12-2013 at 06:28

Good find, DA!

turd - 21-12-2013 at 06:40

And Na becomes non-metallic:
http://phys.org/news156104532.html

These kind of things are not really news and certainly not "the beginning of a revolution in chemistry". Interesting chemistry but terrible article.

bismuthate - 21-12-2013 at 06:40

That makes me wonder, if NaCl3 exists how about NaBr3 or Na2O3 or any other compounds of the like?

blogfast25 - 21-12-2013 at 06:55

Quote: Originally posted by turd  
These kind of things are not really news and certainly not "the beginning of a revolution in chemistry". Interesting chemistry but terrible article.


It's not a 'terrible' article. The term 'revolution' is over-used in general but other than that it's a good read for a digest.

turd - 21-12-2013 at 07:35

Well, de gustibus non est disputandum. But this is one of the worst pieces of science journalism that I have ever seen - and that means something. Compounds that violate text book rules are made all the time. Stable radicals, 17e- complexes, etc. Likewise two-dimensional conductors and layered structures are a dime a dozen. If you apply exotic conditions you will get exotic materials, duh. I'm superficially familiar with this group's work since there is a small high-pressure hype going on at the moment and think it is pretty cool. But this article actually made me lose some respect for them (I hope the hysteric hyperbole was the work of the "journalist").

Eddygp - 21-12-2013 at 07:45

You could apply this to many things, not only "new" chemical compounds, but maybe allotropes and alloys made up of metallic-allotrope non-metals (at high pressures), such as H, and metals. You could study the way it decomposed when depressurising the whole "alloy" afterwards, as it would probably not stay in place, but fall like powder while the H2 escaped as a gas.
Some allotropes form at different pressures and temperatures. I have always wanted to answer a question: how do you know that there isn't an infinite number of, say, tellurium allotropes, if you have never tested every single temp/pressure combination? Not a fan of inductivism.

Random - 21-12-2013 at 07:57

This makes me wonder as some gasses become metals and things like these compounds, the chemistry we know usually is only related to our environment. Somewhere far away in the universe in different conditions there may be totally different chemistry properties alltogether.

O. Ruff - 21-12-2013 at 09:39

Like blogfast and turd, what upset me about this article was that it was too far-reaching in its conclusion. The article seemed to be so hyped-up about, IMHO, something that can already be explained through the current theory.

Now this article, which describes a significant increase in reaction rate of methanol at low T, I find very interesting: http://tinyurl.com/nkaocj4

blogfast25 - 21-12-2013 at 14:31

Turd:

Every time you mention this article it gets worse! Maybe your own confirmation bias is at work? ;)

Zyklon-A - 21-12-2013 at 19:07

Quote: Originally posted by Bot0nist  
That is really cool. I recently saw a bit on tv that talked about how hydrogen will form a metallic allotrope I guess is the word, using very high pressures and temperatures with lasers of some form. Ill search around for a link.



[Edited on 21-12-2013 by Bot0nist]

Hydrogen acts a lot like a metal in compounds also.

ChemNews: New Salt Compounds Challenge the Foundation of Chemistry

mayko - 22-12-2013 at 06:19
Quote:

"I think this work is the beginning of a revolution in chemistry," Oganov says. "We found, at low pressures achievable in the lab, perfectly stable compounds that contradict the classical rules of chemistry. If you apply the rather modest pressure of 200,000 atmospheres -- for comparison purposes, the pressure at the center of the Earth is 3.6 million atmospheres -- everything we know from chemistry textbooks falls apart."


http://www.sciencedaily.com/releases/2013/12/131219142138.ht...


I'm not an expert on high pressure engineering, but it seems like this is an area where home scientists could have a lot to contribute ... benign, commonplace substances under extreme, but not ludicrous conditions.


blogfast25 - 22-12-2013 at 06:24

Someone beat you to it:

http://www.sciencemadness.org/talk/viewthread.php?tid=28064

Mesa - 22-12-2013 at 09:45

The transparent Sodium was interesting... They never define it as a solid/liquid though.

The NaCl3/Na2O3/etc. salts probably wont have any relevance to me outside of theory for at least the next decade, hence not so interesting. :(

I wonder if NaH(>2) is possible/stable though...

Brain&Force - 22-12-2013 at 22:10

Is there any information on the possible structure of the compounds? I wonder if the ion Cl3- can make stable compounds at room temperature in aqueous solution or in air. Possibly with a large cation like Cs.

DraconicAcid - 22-12-2013 at 22:22

Quote: Originally posted by Brain&Force  
Is there any information on the possible structure of the compounds? I wonder if the ion Cl3- can make stable compounds at room temperature in aqueous solution or in air. Possibly with a large cation like Cs.


The link does show the crystal structure of NaCl3. It contains three Cl2 ions (of whatever charge) and two Na ions. It's not analogous to the well-known KI3.