Yale-Led Team Solves Half-Century Carbon-Crystal Mystery 42
slew writes "Unlike its more famous carbon cousins: diamonds and fullerenes, you've probably never heard of M-Carbon, but this form of compressed graphite which is as hard as diamonds has baffled researcher for half a century. Over the past few years, many theoretical computations have suggested at least a dozen different crystal structures for this phase of carbon, but new experiments showed that only one crystal structure fits the data: M-carbon."
M-Carbon? (Score:5, Informative)
Nice of TFS to not link to anything describing M-carbon.
Maybe this will help. [newscientist.com] Maybe it was "common knowledge", but I personally hadn't heard of the stuff till now.
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the newscientist article doesn't sound like it's talking about m carbon.
To quote the article I referenced:
Graphite and diamond are the most familiar, while more exotic allotropes include graphene, with versatile electrical properties, and M-carbon and Bct-carbon, which rival diamond's legendary hardness.
with following links to graphene, M-carbon, and Bct-carbon.
Re:M-Carbon? (Score:5, Informative)
Bad form to reply to myself, but this might actually prove useful:
A new superhard form of carbon [stonybrook.edu]
And I'm too drunk to make the decision for y'all. It appears to me like it alternates between 7-sided and 5-sided carbon polygons, rather than the usual 6-sixed polygons in a sheet of graphene. It beats me how this would do anything but form a sheet of its own. It still seems like a two-dimensional structure, but I'm not organic chemist.
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That picture shows the structure, but lacks the 3D depth cues to understand it. Imagine the bond lengths between the carbons are essentially identical (most likely case), and then you can see that it is in fact very "rough". My bet is that prevents slipping by straight friction, just like how graphite is used as a lubricant because the flat plates slide past each other so well.
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Possibly as significant is the discovery of a +5 Inf 1st post...
Which researcher? (Score:5, Funny)
Though he has been baffled, his name has not been released.
Re:Which researcher? (Score:4, Funny)
Another 5 years... (Score:3)
and M-Carbon can be the new Gorilla Glass. Needs a practical industrial process to make it economical, but the raw materials and process energy are cheap enough.
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It looks like something that's already cheaper to fabricate than synth diamond, so it has a good chance of replacing diamond in most industrial applications.
Toughness? (Score:4, Insightful)
If it's tough and hard, we could be onto a winner.
Re:Toughness? (Score:5, Informative)
Hardness and toughness are pretty much opposites. when a crystal deforms it does so along slip plains and the harder something is the less available slip plans are available for the material to deform which is why diamonds are used in hardness testing (the softer the material the bigger impression the diamond makes on the material (google vickers hardness test) .
From wikipedia
In materials science and metallurgy, toughness is the ability of a material to absorb energy and plastically deform without fracturing;[1] Material toughness is defined as the amount of energy per volume that a material can absorb before rupturing. It is also defined as the resistance to fracture of a material when stressed.
So as a Diamond is hard due to lack of available slip plains its toughness is lowered due to its inability to deform. Therefore it is unlikely that this new material will be tough. (that says nothing about tensile strength just it's ability to deal with a sharp blow).
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http://www.popsci.com/technology/article/2011-01/new-metallic-glass-toughest-strongest-material-yet [popsci.com]
http://www.livescience.com/10420-metallic-glass-hard-tough.html [livescience.com]
Some choice quotes:
"Strength refers to how much force a material can take before it deforms. Toughness exp
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Extremely high compressibility (Score:5, Informative)
It seems that the anisotropy does give a lower compressibility, but not dramatically more as in graphite (weaker plane compressibility is 2.7% of the stronger plane). It's also clear that the diamond in the diamond anvil cell used to make this is damaged by the material. The picture in the Yale News article is the damaged anvil, not the M-carbon. In SEM images, it doesn't look like graphite at all, but more like fused grains. Characterization and proof of structure is done by X-ray diffraction [wikipedia.org], a standard materials science method, using synchrotrons [wikipedia.org], which are giant particle accelerators, namely ALS at LBL [lbl.gov] and APS at Argonne [anl.gov].
where's the info? (Score:1)
I read the godawful article.
First it says that this state was theoretical - meaning that we know the crystal structure, because the crystal structure is the theory.
Then it says they made some. Ok, so they confirmed the theory, right? And that's what's new?
Then it says the structure has been mysterious for fifty years, as though they had made some experimentally, but had no theory to describe it.
So which is it? Is the theory new, and the material has been around all along, or is the material new and the c
Re:where's the info? (Score:5, Informative)
When you cold press graphite you get new forms of carbon that are not graphite and are not diamond. It damages the diamond anvils in your compression apparatus, so it seems to be as hard as diamond. But nobody could figure out what the crystal structure was, even though several theoretical structures had been proposed. These guys have shown that only one of those structures, M carbon, fits the experimental data.
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Re:Post is not very helpful (Score:5, Informative)
I started Googling and what I found is that some scientists [cleantechnica.com] have been playing with graphite and compressing it. They found that, at room temperature and high pressures, graphite goes from black to colorless and becomes very hard. They lacked the ability to determine the precise structure of the super hard carbon. They just knew it wasn't diamond.
Around the same time, some theoretical mineral physicists [stonybrook.edu] came up with some math that says that carbon can have any number of forms with different properties and configurations. These configurations were labeled with letters, lacking any pattern I can discern. (Maybe they labeled an initial list and then began disqualifying configurations?)
The article in the summary essentially is saying that they have linked the 2 bits of data and have determined that the super hard carbon is in fact the M carbon. Nothing I have found gives us any information on the duration of the M carbon once the pressure is removed or any properties of M carbon, except that the hardness is greater than diamond's. I guess we'll have to read the paper.
What a badly written piece (Score:5, Insightful)
This is really badly written. It's missing several obvious and important pieces of data.
For example, what was the experiment they did in which they damaged diamond? The way it's described “Our study shows that M-carbon is extremely incompressible and hard, rivaling the extreme properties of diamond so much that it damages diamond,”, it sounds like the very existence of the material damages all diamond everywhere.
And what the heck is the crystal structure anyway? I know what the atomic arrangement of graphite is, and I know what the atomic arrangement of diamond is, but what the heck is 'M-Carbon'? How are the atoms arranged there? The article gives no clue.
And lastly, the article hints that after M-Carbon (whatever that is) has been created with extreme pressure, it stays that way even after the pressure is released. But it doesn't outright actually say it anywhere. Does it?
Three important and obvious questions that the article totally fails to address. All the while tossing around fluff data that's vaguely interesting, but ultimately not important, or tantalizing hints at important things, but no followup. It's annoying. The writer responsible for this piece ought to be given some obnoxious and menial task and then let out to re-write the piece periodically, repeating until it's actually halfway decent.
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Only one logical fallacy fits the headline: tautology.
What is tautology? For years Scientists have been baffled by this logical fallacy. Recent research has indicated it can be only one thing: tautology.
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Oh, that is pretty interesting to know. I wonder if they could make m-carbon-anvil presses. :-)
The actual article (Score:3, Informative)
can be found here http://www.nature.com/srep/2012/120719/srep00520/full/srep00520.html (OPEN ACCESS).
Wait... (Score:3)
What exactly was this stuff called _before_ they (theoretically) discovered it's made out of M-Carbon? Did the researchers just go around saying "Hey, you want to do some tests today on that carbon stuff that's as hard as diamonds but is produced at room temperatures under high pressure instead of both high pressure and high temperatures"? Seems like a mouthful.
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Parent here. It also appears that the authors of this paper from 2010 sure know a lot about M-Carbon's structure for something that the article implies was discovered by Yale. What Yale discovered was that the configuration of the super-hard material they tested was comprised by M-Carbon and not bct-Carbon, not the structure of M-Carbon. Also, that link goes to a PDF, sorry for neglecting the disclaimer.
Graphic representation (Score:2)
Of the crystaline structure of M-Carbon can be seen in this article http://rdmag.com/News/2012/06/Materials-Researchers-Establish-Structure-Of-A-New-Superhard-Form-Of-Carbon/ [rdmag.com]