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Yale-Led Team Solves Half-Century Carbon-Crystal Mystery 42

Posted by timothy
from the fold-here-bend-there dept.
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."
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Yale-Led Team Solves Half-Century Carbon-Crystal Mystery

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  • M-Carbon? (Score:5, Informative)

    by Mal-2 (675116) on Sunday July 22, 2012 @01:19PM (#40730513) Homepage Journal

    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.

    • by funkboy (71672)

      Possibly as significant is the discovery of a +5 Inf 1st post...

  • by Anonymous Coward on Sunday July 22, 2012 @01:19PM (#40730515)

    this form of compressed graphite which is as hard as diamonds has baffled researcher

    Though he has been baffled, his name has not been released.

  • by JoeMerchant (803320) on Sunday July 22, 2012 @01:22PM (#40730525)

    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.

    • by Hentes (2461350)

      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)

    by Twinbee (767046) on Sunday July 22, 2012 @01:27PM (#40730567) Homepage
    How 'tough' is this M-carbon in comparison to diamond? Actual diamond is very hard, but its toughness is only average, and hence quite brittle like glass.

    If it's tough and hard, we could be onto a winner.
    • Re:Toughness? (Score:5, Informative)

      by blackest_k (761565) on Sunday July 22, 2012 @01:41PM (#40730651) Homepage Journal

      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).

         

    • by h4nk (1236654)
      it goes to 11?
    • by vuo (156163) on Sunday July 22, 2012 @05:44PM (#40731867) Homepage
      From the original Scientific Reports article: [doi.org]

      We find the bulk modulus of M-carbon to be 365+/-38 GPa, thus is one of the stiffest materials known comparable to that of cubic-BN (387+/-4 GPa) and wurtzitic BN (375+/-9 GPa). ... M-carbon also shows anisotropic compressibilities along lattice axes: the a axis is stiffest [527+/-2 GPa] and the b [271+/-1] and c [267+/-1 GPa] axes are roughly equivalent ...

      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].

  • by Anonymous Coward

    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)

      by ceoyoyo (59147) on Sunday July 22, 2012 @02:03PM (#40730759)

      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.

      • It might be a good idea to note, that "traditional" method of crystal structure determination - X ray diffraction - requires you to have at least some crystalline sample, it destroys the sample in the process, and gathering enough data to form a good pattern takes some time. Furthermore, you need considerable computational expense to interpret the diffraction patterns (which is a fourier transform of the actual structure) - the phase of the FT is unknown. For molecules (or even polymers or proteins), it's q

  • by Omnifarious (11933) * <eric-slashNO@SPAMomnifarious.org> on Sunday July 22, 2012 @01:38PM (#40730639) Homepage Journal

    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.

    • Re: (Score:2, Funny)

      by Anonymous Coward

      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.

  • The actual article (Score:3, Informative)

    by Anonymous Coward on Sunday July 22, 2012 @02:40PM (#40730951)

    can be found here http://www.nature.com/srep/2012/120719/srep00520/full/srep00520.html (OPEN ACCESS).

  • by Daetrin (576516) on Sunday July 22, 2012 @02:46PM (#40730983)
    So the blurb starts out by describing this stuff as M-Carbon, then goes on at the end to say they've discovered it's made out of.... M-Carbon!

    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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