Nanotubes are for wusses.

November 7, 2013 1:10 AM

Theoretically sound model for metallic carbon found. Researchers from Peking University, Virginia Commonwealth University and Shanghai Institute of Technical Physics employed state-of-the-art theoretical methods to show that it is possible to manipulate carbon to form a three-dimensional metallic phase with interlocking hexagons. “Unlike high-pressure techniques that require three terapascals of pressure to make carbon metallic, the studied structures are stable at ambient conditions and may be synthesized using benzene or polyacenes molecules." The new metallic carbon structures may have important applications in lightweight metals for space applications, catalysis and in devices showing negative differential resistance or superconductivity. The research is supported by grants from China and the US Department of Energy.
posted by markkraft (23 comments total)

One of the rules of thumb in chemistry is that elements in a column of the periodic table tend to behave similarly. So, metallic carbon should be somewhat like the metallic forms of the other members of group 14: Silicon, Germanium, Tin and Lead. None are particularly structural or conductive. Si & Ge are famous as semiconductors, perhaps metallic carbon would be as well, but could it be fashioned into useful forms?
posted by eriko at 4:36 AM on November 7, 2013 [1 favorite]

So, metallic carbon should be somewhat like the metallic forms of the other members of group 14: Silicon, Germanium, Tin and Lead.

Structure matters a lot. Do silicon, germanium, tin, or lead have "interlocking hexagon" allotropes?
posted by a snickering nuthatch at 4:44 AM on November 7, 2013

Clearly, we just need to combine this discovery with the one about absorption of carbon from the atmosphere in order to use greenhouse gases to grow cities built entirely from carbon. Climate change solved. Make checks payable to Mr. S.M. Machine, Esq.
posted by sonic meat machine at 5:10 AM on November 7, 2013 [6 favorites]

Graphene is remarkably different from any structural forms of the other group member (although people are just beginning to look at silicene, the silicon equivalent, it will probably not behave anything like graphene due to very strong inter-layer bonds, at least as I understand it).

I wouldn't think that this new structure, if it can be made in useful quantities, will be as revolutionary as graphene in terms of fundamentally new physics properties, but it could well make awesome new construction materials. The references to superconductivity and negative resistance, though... anyone got a non-subscription link to the full paper?
posted by Devonian at 5:11 AM on November 7, 2013 [1 favorite]

Make checks payable to Mr. S.M. Machine, Esq.

A good point. I wonder how the Bayh-Dole act - which gives public universities the title to inventions made with public money - will come into play. I can imagine that because this is shared with Chinese investment, it will be a bloody mess to sort out to whom the checks will be sent.
posted by three blind mice at 5:14 AM on November 7, 2013

There might have been some birthrights signed away, but the likelihood of bloodshed at this point is going to be nil.

Intellectual property rights arrangements were going to be a condition of any independent funding received.
posted by ardgedee at 5:42 AM on November 7, 2013 [1 favorite]

Are there any chemists out there who would care to speculate on the degree to which "may be synthesized using benzene or polyacenes molecules" might be likely to yield real world result?
posted by rongorongo at 5:48 AM on November 7, 2013

rongorongo: "Are there any chemists out there who would care to speculate on the degree to which "may be synthesized using benzene or polyacenes molecules" might be likely to yield real world result?"

Not a chemist, but Benzene is nasty, nasty stuff (in the particularly evil "kills you slowly over time" kind of way). It's not exactly uncommon in industry, but you won't find many people who would want to develop new manufacturing processes around it.
posted by schmod at 6:20 AM on November 7, 2013

The references to superconductivity and negative resistance, though... anyone got a non-subscription link to the full paper?

I, too, would be interested to see the full paper to hopefully* better understand how they came up with those possibilities, given that as near as I can tell from the picture and the reference to "hexagonal arrangement ... with tetrahedral bonding" in the second article, they are breaking the aromaticity that makes graphene so interesting electronically.

*I've been out of the field long enough that even with the full article I might not understand, especially since I never was a p. chemist. Would love to TRY to understand, though!
posted by solotoro at 6:56 AM on November 7, 2013

aromaticity
 
posted by Herodios at 7:05 AM on November 7, 2013

Could someone by any chance provide a link to the "discovery about carbon absorption from the atmosphere" that sonic meat machine mentioned above? I'd love to read about it. A practical method for large-scale drawdown of atmospheric carbon would be a huge deal, needless to say. If there's something on the horizon that shows real promise in that arena I'd be excited to learn about it.
posted by Scientist at 7:17 AM on November 7, 2013

anyone got a non-subscription link to the full paper?

I'll send a copy to anyone who memails me.
posted by Maecenas at 7:29 AM on November 7, 2013

Intellectual property rights arrangements were going to be a condition of any independent funding received.

Well that's the problem.

The research is supported by grants from China and the US Department of Energy.

IPR arrangements for the U.S. side are covered by the Bayh-Dole act: The DoE has no say in the matter and the U.S. taxpayer gets nothing as a condition for its financial support. It is entirely unclear what position the Chinese government will take and I do not imagine that they give research money away with no-strings-attached like the U.S. government does.
posted by three blind mice at 7:35 AM on November 7, 2013

Are there any chemists out there who would care to speculate on the degree to which "may be synthesized using benzene or polyacenes molecules" might be likely to yield real world result?

A quick look at the figures and it looks like a repeating cyclohexadiene structure, with spiro centres at the one and four positions (ie. no hydrogen, double bonds on either side). Aromaticity is blocked due to the spiro centres.

I'm not familiar with any simple way to make that many spiro centres, though perhaps you could do something with carbenes built from long acene chains reacting with cyclobutadiene (the carbenes react with cyclobutadiene to form highly strained cyclopropanes, which then break open to form the necessary cyclohexadiene). If a route is found through benzene the toxicity wouldn't be a concern (though it is a strong carcinogen, industry routinely works with far worse). Wikipedia says we used 24 million tons of benzene back in 1999, and I doubt that has gone down much since.
posted by Orange Pamplemousse at 8:02 AM on November 7, 2013 [2 favorites]

Did Scottie "invent" this one too?
posted by Curious Artificer at 8:05 AM on November 7, 2013

China isn't giving money due to their gracious appreciation for theoretical learning, and the recipient university is not naive enough to assume they want no proprietary interest. Their mutual and conflicting interests were resolved on paper before any grant money exchanged hands. This is what grants contracts do. Neither party is run by idiots, regardless of how you might stereotype them.

Intellectual property rights in China are not covered by US law, and vice versa. China can do any damn thing it wants with the information within their own country, assuming applications are viable. U.S. courts can only intervene if products exploting any patents are imported here.

So to the extent it was ever an issue, it was settled before the grants were given. This is a derail.
posted by ardgedee at 8:06 AM on November 7, 2013 [1 favorite]

Scientist: "Could someone by any chance provide a link to the "discovery about carbon absorption from the atmosphere" that sonic meat machine mentioned above? I'd love to read about it. A practical method for large-scale drawdown of atmospheric carbon would be a huge deal, needless to say. If there's something on the horizon that shows real promise in that arena I'd be excited to learn about it"

Here's an article from 2010, there were also a couple new articles in the last month or so.

Here's an announcement about a pilot plant that is planned.
posted by ArgentCorvid at 8:10 AM on November 7, 2013 [1 favorite]

Such a product could finally put an end to the carbon vs. steel bike debate. It's a floor wax AND a dessert topping.
posted by jetsetsc at 8:55 AM on November 7, 2013 [1 favorite]

Can somebody please explain "negative differential resistance"? Especially the 'differential' part.
posted by newdaddy at 9:31 AM on November 7, 2013

sonic meat machine: "Clearly, we just need to combine this discovery with the one about absorption of carbon from the atmosphere in order to use greenhouse gases to grow cities built entirely from carbon. Climate change solved. Make checks payable to Mr. S.M. Machine, Esq."

Yeah, and then the army of nanobots designed for this process runs out of atmospheric carbon and before anybody can figure out a way to disable them their swarm intelligence discovers and turns to an alternative source: us. Strange corpse-like ornaments begin to appear in architecture. Vaguely humanoid shapes appear to be fused into and protruding from the metallic carbon walls of new city buildings, wrapped as frames around windows, faces twisted into gargoyle shapes by unfathomable pain and horror.
posted by Hairy Lobster at 9:42 AM on November 7, 2013 [1 favorite]

Can somebody please explain "negative differential resistance"? Especially the 'differential' part.

Here's a resistor:

+---------+---------+
| current | voltage |
+---------+---------+
|   10    |    20   |
|   20    |    40   |
|   30    |    60   |
|   40    |    80   |
|   50    |   100   |
|   60    |   120   |
+---------+---------+

Voltage
^
|             _.
|          _./
|       _./
|    _./
|  ./
+--------------> Current

Most of the time, current and voltage across a resistor are proportional to each other. In a passive resistor like this, your graph looks like a straight line going generally diagonally upward. Other components might have curves to them but they still trend upward as you go to the right. But here's a circuit element with negative differential resistance:

+---------+---------+
| current | voltage |
+---------+---------+
|   10    |    20   |
|   20    |    50   |
|   30    |    40   |
|   40    |    30   |
|   50    |    40   |
|   60    |    50   |
+---------+---------+

Voltage
^
|             ./
|           ./
|    ._   ./
|   /  \_/
|  /
+--------------> Current

In some funky components (like neon lamps), when operating in a certain range of voltages and currents, increasing the current decreases the voltage! We call it negative "differential" resistance because we're talking about changes- saying "increase the current a little bit, and the voltage decreases a little bit". That's the downward sloping bit of this graph.
posted by a snickering nuthatch at 10:14 AM on November 7, 2013 [2 favorites]

Thanks Jpfed! I appreciate it!
posted by newdaddy at 10:17 AM on November 7, 2013

Thanks, ArgentCorvid! Interesting concept. Will be neat if it works out, though I'm not holding my breath.

(Instead, I'm breathing into a tank of genetically-altered yeast solution.)

Also it looks like they want to use it more for carbon capture than carbon drawdown? That is to say, they are not hoping that this will provide a way of reducing the amount of CO₂ in the atmosphere, but rather a way of preventing some of it from escaping at major centralized CO₂ emissions sites like power plants and large factories? The press release is a bit vague, but that's the impression I got. That would be a good thing, but obviously not a solution to climate change.

To have a big impact you'd have to retrofit many thousands of existing carbon sources around the world and mandate its inclusion in new industrial designs worldwide. Even then you'd still be doing nothing about CO₂ released as a result of transportation (i.e. cars) which is the biggest source of emissions, not to mention other distributed greenhouse gas sources, and nothing about the already-dangerous levels of CO₂ in the atmosphere today.

OK, derail over.
posted by Scientist at 1:29 PM on November 7, 2013 [1 favorite]