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Science

Scientists Create Compound With a Single Element 163

Posted by samzenpus
from the a-bit-of-a-hermit dept.
rocketman768 writes "An international team of researchers including scientists at the Carnegie Institution has discovered a new chemical compound that consists of a single element: boron. Chemical compounds are conventionally defined as substances consist of two or more elements, but the researchers found that at high pressure and temperature pure boron can assume two distinct forms that bond together to create a novel 'compound' called boron boride."
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Scientists Create Compound With a Single Element

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  • Eh? (Score:5, Insightful)

    by Dyinobal (1427207) on Wednesday February 04, 2009 @10:13PM (#26732583)
    I think my head just exploded. Compound, of one element. What next transparent aluminum?
  • I don't understand (Score:5, Interesting)

    by DigitAl56K (805623) * on Wednesday February 04, 2009 @10:17PM (#26732621)

    Why is this not an allotrope [wikipedia.org]? I'm not a chemist so excuse me if the answer seems obvious to those with a better understanding.

    • by snowgirl (978879) * on Wednesday February 04, 2009 @10:24PM (#26732663) Journal

      Why is this not an allotrope [wikipedia.org]? I'm not a chemist so excuse me if the answer seems obvious to those with a better understanding.

      That's exactly what I was wondering. The title made me wonder "what? graphite? diamonds?"

    • by snowgirl (978879) * on Wednesday February 04, 2009 @10:32PM (#26732715) Journal

      Reading the intro paragraph of the article, I have an answer.

      This is an IONIC compound. Someone felt that it was an unnecessary or unimportant distinction to make.

      It's the first IONIC compound to be composed of only one element.

      • Isn't that what things like O2 are, also? Or am I remembering my high school chemistry incorrectly?

        • by NotSoHeavyD3 (1400425) on Wednesday February 04, 2009 @11:45PM (#26733325)
          Basically an ionic compound is formed when one part has a whole positive charge and another has a whole number negative charge. So table salt consists of Sodium Chloride or a Sodium that has a +1 electric charge and a Chlorine with a -1 charge. (Opp attract so they stick.) However O2 isn't held together because one oxygen atom has one charge and the other doesn't. Instead they form a covalent bond which is basically the 2 oxygen atoms share electrons and that's what makes them stick to each other.
          • Yeah, I figured that out when I read further down in the comments.

            But thanks for explaining it. You did a better job than some of the others.

          • by Giant Electronic Bra (1229876) on Thursday February 05, 2009 @12:51AM (#26733797)

            Not to say you are at all wrong, it is a good explanation, but the distinction between 'ionic' and 'covalent' bonds is really one of a matter of degree between 2 extremes.

            At the one extreme we have single element compounds like H2 or O2 in which the electronegativity of the component atoms is (by definition) equal and thus have an even charge distribution and are entirely covalent. This is the simplest case.

            At the other extreme we have substances like NaCl which are made up of atoms with extremely different electronegativities. However there is no such thing as a purely 'ionic' bond. Even in an extremely polar molecule like NaCl the charge distribution isn't ENTIRELY Na+1 and Cl-1. It very nearly is, but not quite.

            MOST compounds are far less clear cut. Even H2O's bonds, which are fairly polar and is composed of 2 species with very different electronegativity the bond is generally characterized as having both an ionic and a covalent character.

            So, our boron boride is also going to be a compound which is not going to be entirely clearly either ionic nor covalent.

            The real problem is that these terms only signify useful generalizations about how chemical species behave. While chemistry CAN be reduced to physics in a reasonably straightforward way in principle, the reality is that most of the terms and most of the ways chemists ordinarily think about chemistry is a set of 'rules of thumb' which are based as much on observation and valued as much for their general utility as they are based on precise formulations of fundamental laws and processes. Even the notion of 'compound' is really to a certain extent a convenience and necessarily gets a bit fuzzy at the 'edges'.

            • by NotSoHeavyD3 (1400425) on Thursday February 05, 2009 @01:28AM (#26733987)
              Oh no doubt of course. I mean they teach you that in chem 101 and that reaction go in one direction for example. Then in chem 102 they start teaching you about how the reactions actually go in 2 direction and don't really stop but hit equalibrium. Of course in orgo they start telling you how what they originally showed to you a compound with distinct single and double bounds really isn't like that and it's sort of a mixed bond. (I mean benzene for example. The first version they might show you has alternating single and double bonds. In reality all the bonds are of the same length and the bonds are actually an intermediary between single and double bonds.) Oh well, just more having fun with chemistry.
            • Re: (Score:2, Interesting)

              by Hognoxious (631665)
              Ionic compounds like NaCl don't exist as molecules under normal conditions.
              • Re: (Score:3, Informative)

                by fireboy1919 (257783)

                You're saying that there's no such thing as table salt. This is obviously false.

                Compounds with strong ionic bonds tend to disassociate completely in water forming the constituent ions (completely being as previously indicated - not really complete).

                However, the moment that they leave the water, they're back to what they were - full molecules again.

                • by HTH NE1 (675604)

                  Compounds with strong ionic bonds tend to disassociate completely in water forming the constituent ions

                  When did the saltwater oceans explode in a chemical reaction with sodium and produce a massive cloud of poisonous chlorine gas in your world?

                  (Sucks to be Utah.)

              • by Gryle (933382)
                Um, what? Perhaps there's a deep layer of philosophical meaning underlying your statement, or perhaps you mean that most ionic compounds are solids in a crystal matrix at room temperature, but I can assure you that sodium chloride molecules and molecules of other ionic compounds do indeed exist under normal conditions (STP). The lab I work in has great big jars of sodium chloride on the shelf. It is also easily generated by the reaction of sodium hydroxide and hydrochloric acid at STP under aqueous conditio
              • Extremely polar molecules like NaCl, salts, are so polar that they hardly share electrons at all. Thus the vast majority of the forces that hold them together are purely electrical charge, as opposed to the case of covalance where the bond is stabilized due to the formation of an energy level which favors stability.

                In these types of compounds there ARE no molecules per-se. There is no one Na+ that is associated with a specific Cl-.

                Still, the original point was that chemical bonds are understood to have both

            • by Anonymous Coward on Thursday February 05, 2009 @06:34AM (#26735175)
              Reduced to physics? Reduced to physics!! Grr. If its being 'reduced' to physics, then is the rest of it unscientific alchemy?
              • Re: (Score:3, Funny)

                by QuantumPion (805098)

                Reduced to physics? Reduced to physics!! Grr.
                If its being 'reduced' to physics, then is the rest of it unscientific alchemy?

                Mathematics. [xkcd.com]

        • No, O2 is a covalent bond, I believe.

        • by jonbryce (703250)

          No. But Ozone Dioxide would be if it existed.

    • by rajkiran_g (634912) on Wednesday February 04, 2009 @10:33PM (#26732727)

      AFAIK, an allotrope is just a different spatial arrangement of atoms without any transfer of electrons. However, in this case, the arrangement is such that there is a transfer of charge from one set of atoms to another.

      From TFA,

      How can an element be ionic? Classical chemistry textbooks indicate that charge transfer occurs when atoms have different electronegativities and this automatically disqualifies pure elements as possible ionic phases. Boron finds a surprising solution to this problem â" its new structure contains two very different types of nanoclusters, B12 icosahedra (blue in the figure above) and B2 dumbbells (orange in the figure above). The electronic structures of these two clusters are very different â" in fact, the dependence of electronic properties on the size of the cluster is well known and is the main idea of nanotechnology. Electronegativities of the B12 icosahedra and B2 pairs are different, and this causes charge redistribution and the emergence of partial ionicity in this elemental structure.

    • by jonnythan (79727)

      This one is a compound made from two different forms of the same element. First of its kind.

  • Boring... (Score:5, Funny)

    by MadCow42 (243108) on Wednesday February 04, 2009 @10:21PM (#26732641) Homepage

    Sorry, had to say it. :)

  • by Dragonshed (206590) on Wednesday February 04, 2009 @10:23PM (#26732651)
  • Puzzled.. (Score:2, Insightful)

    by UPZ (947916)
    Whats the difference between that, and say, N2 or O2? Aren't those also compounds of a single element?
    • Re:Puzzled.. (Score:5, Informative)

      by argent (18001) <peter.slashdot@2006@taronga@com> on Wednesday February 04, 2009 @10:41PM (#26732787) Homepage Journal

      they're covalent, not ionic.

    • Re:Puzzled.. (Score:5, Informative)

      by Anonymous Coward on Wednesday February 04, 2009 @10:42PM (#26732807)

      Whats the difference between that, and say, N2 or O2? Aren't those also compounds of a single element?

      With oxygen and nitrogen the two atoms are identical for all intents and purposes. They share electrons evenly. In this case you have boron atoms that are giving up electrons and boron atoms that are accepting them to reach a stable state. So they're behaving differently, rather than the same.

      • by Toonol (1057698)
        What about... two hydrogen atoms sharing one electron? Wouldn't one be an electron donor and the other a receptor? Or is that splitting hairs? (Honestly, I don't even know if that bond is possible.)
        • I'm pretty sure you can probably get those two to bind together with some work. What I'd like to know is if you could get two of them to stick to an oxygen atom and sort of share their electrons amongst them. Honestly - is that bond even possible? Well, I suppose by now someone has managed it.

          • Which you've described reasonably well. 2 H's and an O will quite happily share electrons and come out of your tap too. That bond is not an 'even split' though, the oxygen holds tighter to the electrons and gets more than its 'fair share' of them.

            Water is somewhat 'sticky' (viscous) because of this fact. The O part of it has a bit of a negative charge, and the H parts a bit of a positive charge, so it is a 'polar' molecule and the H side of one water sticks a bit to the O side of the next one. This gives wa

        • Common hydrogen gas, is 2 hydrogen atoms sharing TWO electrons. It is a reasonably stable and entirely covalent compound. That is you cannot say that one hydrogen has BOTH electrons and the other hydrogen has none. Each one has a 'share' of both electrons at once, and that share is exactly equal.

          The difference with this boron boride is that some of the boron atoms have a bigger share of the electrons than others, which is at the very least pretty unusual for a compound with only one type of element in it.

          By

          • by ceoyoyo (59147)

            It sounds like it's not actually the boron atoms that configure themselves differently, but rather groups of boron atoms. So you don't really have a boron-boron compound (Chem 101 is still technically right), but more of a boron allotrope 1 - boron allotrope 2 combination. Kind of like a single element alloy, or a semiconductor doped with itself.

        • by cnettel (836611)
          Two hydrogen atoms sharing one electron would just have a single orbital, which is equally shared. However, that orbital is repelling, the energy state of a free unbound hydrogen atom and one proton would be more favorable.
    • You have to have electro negativity charge difference > 2 in order to be considered ionic.

      • All bonds between different species are at least PARTLY 'ionic' in character. At least until now though NO bonds between like species have demonstrated ANY ionic character (at least that I know of). So it is interesting.

    • by DeadChobi (740395)

      As I'm sure has been repeated, it appears that this is a compound of Boron where the Boron exists in two different covalently bonded structures, with different electronegativities. This results in the two structures forming ionic bonds.

  • Call me when they make Hydrogen HexaHydride!
    • by hedwards (940851)

      I know that you're joking but...

      That's definitely not going to work. It's highly unlikely that anything with fewer electrons than Li is going to be capable of doing that sort of sorcery. Doing it with Boron is kind of neat.

      And on top of that it's unlikely that an odd number of atoms is going to work without the atoms having an even number of electrons.

      Of course it's been a long time since I took chemistry so I might be wrong.

  • Related (Score:5, Funny)

    by Walkingshark (711886) on Wednesday February 04, 2009 @10:45PM (#26732821) Homepage

    Boron Boride, the nobleman? This discovery is an abomination, like the Boride of Frankenstein. And isn't Boron the cousin of the famous Ukranian trumpet player, Boris Boride? I know, my jokes are so bad you must think I'm a total stupid boron. What happens when you drill the surface of something? You boron it. What happens when the drill goes out of control and starts flopping all over the place and you're stuck on top? Boron bo-ride!

    Ok I'll stop.

  • Miswritten summary (Score:5, Informative)

    by blueg3 (192743) on Wednesday February 04, 2009 @10:57PM (#26732935)

    Frankly, the article is interesting enough without mangling it in the summary.

    This is the first ionic crystal to consist of only one element. As a compound, by definition, contains two elements, it's not a compound. A boron ionic crystal is substantially different from, say, the multiple allotropes of carbon, though.

    However, this is a solely theoretical crystal -- it hasn't been synthesized.

    • by Rutulian (171771) on Thursday February 05, 2009 @12:42AM (#26733745)

      Actually it has been synthesized. The structure was determined using a computational method, though. In other words, they couldn't use standard techniques to interpret the x-ray diffraction data and had to use the evolutionary structure prediction method mentioned in the paper.

      What I find kind of amazing is the news article mentions a Vickers hardness of 50 GPa. The journal article doesn't mention anything about that, unless it is somewhere in the supplementary materials, but anyway, if the news article estimated correctly based on the reported phase transformation pressures...that's pretty damn hard!

      • by Tellarin (444097)

        Isn't it basically just the same as regular Boron (49GPa)?

        • by Rutulian (171771)

          Honestly, I'm not sure how to interpret these things because hardness can mean so many different things. But, as the article mentioned, until now (actually a few years ago) an elemental Boron hasn't been known. All known polymorphs had been found to be contaminated with impurities.

      • by CaptDeuce (84529)

        ... if the news article estimated correctly based on the reported phase transformation pressures...that's pretty damn hard!

        Is that boron boride in your pocket or are you just happy to see me?

  • Did anyone else read that as "Single scientists join compound for singles...".
  • Boron Boride: Buzz Killington's [wikipedia.org] little brother...

  • Na-Na+ (Score:5, Interesting)

    by TeknoHog (164938) on Thursday February 05, 2009 @02:09AM (#26734137) Homepage Journal
    In the mid-1990s I studied with the book Chemistry in Context by Hill and Holman. The companion book of experiments and real-world applications had a chapter on anions of alkali metals, and it included a picture of the crystalline self-compound Na-Na+.
  • The structure could not be solved from experimental data alone, and required a new theoretical method that was developed by Dr. Oganov at the time [2004].

    "The method is a purely theoretical, requires no experimental information, and is based on ideas of natural evolution applied to the search for the most stable crystal structure," said Dr. Oganov. "The computer generates dozens of trial crystal structures, whose energies are evaluated using quantum-mechanical calculations, and the most favorable of the sam

  • I bet California has already declared it to be cancer-causing..

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