Talk:Diborane

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Why are all types of compounds of boron monomers with the exception of diboranes and other boron hydrides? Can you explain why structure of diborane is unusual? example: BCl3, BI3 are monomers of trivalent boron; whereas B2H6 or (BH3)2 is a dimer having unusual structure.

In BCl₃ and BI₃, there is donation of electron density from the filled p-orbitals on the halides to the vacant p-orbital on boron, stabilising the boron monomer. With hydrogen, no such donation is possible as it has only one electron and no occupied p-orbitals. I will eventually add this (and other information) to the article, after I have finished adding to Borane--Amigadave 11:45, 2005 Apr 26 (UTC)

Also, if you think that B2H6 is strange, Al2Me6 is analogous, with two bridging methyl groups (five coordinate carbon).Smokefoot 14:00, 31 January 2006 (UTC)

please give the preparation of B2H6 - how is it manufactured?

Image?

We could really use a picture of the borane dimer. DS 16:44, 19 September 2005 (UTC)

Alumane?

Is this Aluminium Hydride? If so it should link to that article.Dajwilkinson 23:53, 15 May 2007 (UTC)

H. Christopher Longuet-Higgins

I have added the name of the undergraduate student. H. Christopher Longuet-Higgins went on to great things as a theoretical chemist and was a member of the International Academy of Quantum Molecular Science. He then changed fields completely to Artificial Intelligence. I will write on article on him sometime but the two fields make it difficult. I'm working through the redlinks on International Academy of Quantum Molecular Science. Of course, if anyone else wants to write it, please go right ahead. --Bduke 00:58, 19 June 2006 (UTC)

MSDS error

It should be a 4,4,3 based on the NOAA guidelines. I have put the link below. https://cameochemicals.noaa.gov/chemical/4943

Contradiction in Terms

What is a "repulsively sweet" odor?71.195.250.188 (talk) 06:01, 17 November 2008 (UTC)

So sweet it's unpleasant?

Ben (talk) 14:32, 17 November 2008 (UTC)

Saccharine? —Preceding unsigned comment added by 122.106.65.110 (talk) 13:52, 8 June 2010 (UTC)

Burned sugar? Materialscientist (talk) 22:30, 8 June 2010 (UTC)

A paradoxical combination of fragrant and unpleasant odors? Like partially-rotted fruits, perhaps?—Tetracube (talk) 23:18, 8 June 2010 (UTC)

Dialane exists and is known

Of the other elements in Group 13, only gallium is known to form a similar compound, digallane, Ga2H6. Aluminium forms a polymeric hydride. No hydrides of indium and thallium have yet been found.[2]

My english is too bad and I don't take the risk to dirty the article, however I want to signal that dialane (Al2H6) exists and is known. See [1]. Kiss kiss, bye bye. —Preceding unsigned comment added by 78.14.173.211 (talk) 16:05, 24 January 2009 (UTC)

You are quite correct, the existence of Al₂H₆ is even mentioned (and referenced) in the article Aluminium hydride.

However, polymeric AlH₃ is far more common and stable than Al₂H₆.

Ben (talk) 17:21, 24 January 2009 (UTC)

Ok Ben, good lack 78.14.173.211 (talk) 00:55, 25 January 2009 (UTC).

Bonds in Diborane

I would like to know how Hydrogen form one electron covalent bond? —Preceding unsigned comment added by 148.168.40.4 (talk) 12:14, 20 February 2009 (UTC)

Dubious claim

I removed the following dubious sentence from the section "Structure and bonding":

The structure is isoelectronic with C₂H₆²⁺, which would arise from the diprotonation of the planar molecule ethene.

First of all, the formula for ethene is C₂H₄, and deprotonation means removal of hydrogen, which would result in an anion, not a cation, as well as having less than 4 hydrogens. That is to say, either C₂H₃^-, or C₂H₂^2-. This is completely inconsistent with the claimed cationic formula C₂H₆²⁺. Going the other way, protonating ethene would give either C₂H₅⁺ or C₂H₆²⁺. The latter matches the formula claimed, however, I have never heard of protonation involving the insertion of a hydrogen into a covalent sigma bond between two carbon atoms. Even if the unstable species C₂H₅⁺ could be further protonated, I highly doubt it would result in something isoelectronic with diborane.

The only way I can see a carbon equivalent of diborane forming is via the dimerisation of the carbocation CH₃⁺, which is unfortunately an extremely unstable carbocation that is very unlikely to exist long enough to dimerise with another instance of itself.—Tetracube (talk) 22:29, 9 March 2009 (UTC)

You misread and then misconcluded, but we are all reading too fast these days, so no big deal. The item you find objectionable said diprotonation, not deprotonation. And C2H62+ would be isoelectronic with diborane. The question is whether this dication would be isostructural. Deprotonation does not mean removal of hydrogen, the term refers to removal of protons.--Smokefoot (talk) 23:07, 9 March 2009 (UTC)

Mea culpa. So it did mean protonation (and on that note, I meant "removal of H⁺", which is equivalent to removing a proton, when I referred to deprotonation. Talk about reading/writing too fast. :-)). I still think it's a dubious claim, though. Would protonating C₂H₅⁺ break the C-C sigma bond, as would be necessary for the resulting dication to be isoelectric with diborane? I highly doubt it.—Tetracube (talk) 23:28, 9 March 2009 (UTC)

I searched the literature for the ethane dication, [C₂H₆]²⁺, and found a paper (G. Rasul, G. K. S. Prakash, G. A. Olah, J. Phys. Chem. A, 2005, 109 (5), pp 798–801) that answers most of the questions posed here:

• "Neutral diborane, B₂H₆, is isoelectronic with the C₂H₆²⁺ dication."
• "the 2e-3c bonded carbonium-carbenium structure 1 is more stable than the doubly hydrogen bridged diborane-type structure 2 by 12.4 kcal/mol."
• however, for the silicon analogue [Si₂H₆]²⁺, "the 2e-3c bonded siliconium-silicenium structure 8 is 8.7 kcal/mol less stable than doubly hydrogen bridged structure 9."

Ben (talk) 00:17, 10 March 2009 (UTC)

"Would protonating C₂H₅⁺ break the C-C sigma bond" Wha? Who said protons break bonds? Diborane enjoys a nice bond with its fellow boron .. At least if one believe the MO's.--Smokefoot (talk) 02:22, 10 March 2009 (UTC)

OK, maybe I'm still stuck in the old-school mindset... I was thinking of the mechanism of adding a proton to the species C₂H₅⁺, which I assume has a sigma bond between the two carbon atoms. The only way to get something isoelectronic with diborane with this process is if the new proton gets inserted between the carbon atoms. But what do I know, maybe from the MO perspective all of this is just trappings from an obsolete theory that has no real basis in reality.—Tetracube (talk) 17:12, 10 March 2009 (UTC)

Diborane is a electron efficient molecule.in this molecule boron undergoes sp3 hybridization. in this molecule to form ethane like structure boron gives fore electrons.and each hydrogen give one electron.12 electrons are obtained. so they can form only 6 covalent bonds only.to ehane like structure 14 electrons are required. —Preceding unsigned comment added by 210.212.222.90 (talk) 08:51, 11 April 2010 (UTC)

Bond angles and bond lengths

The only reference I can find has different B-H bond lengths from the ones in our pretty picture. Has anyone got a reference for the bond lengths we use? Axiosaurus (talk) 12:12, 28 September 2013 (UTC)

Consensus is emerging at Wikipedia talk:WikiProject Chemistry to revert and rethink the borane articles. At least that is my guess because we dont want the readership being tricked into thinking that BH3 is a major reagent or actor in much chemistry, so it would be discussed within a great context. But that is only my guess the way this article development would go. The B-H distance of the monomer is however useful. In general I think that we need a structural report for as articles on chemical compounds.--Smokefoot (talk) 14:42, 28 September 2013 (UTC)

Assessment comment

The comment(s) below were originally left at Talk:Diborane/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

Recommended for A-Class on Wikipedia:WikiProject Chemicals/List of A-Class articles. Wim van Dorst (Talk) 21:06, 17 February 2007 (UTC).

Last edited at 21:06, 17 February 2007 (UTC). Substituted at 13:22, 29 April 2016 (UTC)

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Electron-deficiency?

Hi. I'm a bit confused here.In the article it is asserted that diborane is electron-deficient, but in the link to the article about electron deficiency it is asserted that it is not. Could someone whose knowledge of chemistry is either more recent or more comprehensive than mine (or both) please clarify? Meltingpot (talk) 09:01, 4 July 2020 (UTC)

First, I have moved this edit to the end of the talk page because it is the most recent subject discussed.

You are correct in saying that there was an apparent contradiction between the two articles. Editor Smokefoot solved this by simply deleting the mention of electron deficiency in this article. However I have restored the mention but in the History section of the article, in order to clarify that electron deficiency in diborane is an older and simpler theory which is still found in some textbooks, even if it is no longer accepted as the most correct description of diborane and other boron hydrides. I have also added more historical perspective to the other article on electron deficiency. Dirac66 (talk) 01:34, 23 July 2020 (UTC)

Sweet odor and toxic? Diborane explodes on contact with air.

How can diborane have a repulsively sweet odor, and, as of an edit today, be toxic? Pyrophoric indeed it is. Some decades ago when with my BB gun I shot a glass ampule containing 1 cc of diborane straight off the vacuum line, it exploded with a loud, sharp, instantaneous crack on contact with air, so no way to smell it or test toxicity, and I made sure I was not downwind. Are we talking about the smell and toxicity of combustion products? Jslipscomb (talk) 17:19, 8 June 2022 (UTC)

• With an autoignition temperature of 38°C, you should be able to inhale enough cold, sparse gas to smell it and live to report the experience. I wouldn't recommend it. 82.12.148.203 (talk) 22:20, 17 October 2024 (UTC)
• I am now 85 years old, but way back as a graduate student I explored the kinetics of the reaction of diborane and alcohol after a paper had been published on the kinetics of the reaction of diborane and water, which is more reactive. The kinetics was studied in an arrangement of glass tubes etc that I removed all the air from before adding the diborane and alcohol. Mostly it worked well but on a few occasions all was not good and I smelt the diborane. It does indeed have a repulsively sweet odor. I survived! Bduke (talk) 02:16, 18 October 2024 (UTC)

  Thank you for the clarification of ignition temerature.

  • Perhaps the combination of the impact of the BB and the vacuum implosion of the glass tube tipped conditions above the ignition temperature. My conditions were test tube in a test tube holder on the roof of a building where I plinked with the BB gun while boron chemistry grad students cheered the larger explosions. No business would do disposal, so improvise.
  • Dborane explosion behavior seemed consistent in these conditions, another example being when an ampule of 1 cc diborane mixed with 5 cc pentaborane (not explosive but flamey) was placed in a sturdy metal Dewar on a fire escape while I kneeled on a sheet of safety glass one story above and shot almost straight down into the Dewar. The crack of the diborane ejected the flamey pentaborane with a flamethrower effect upwards 2 stories high just past my head.

  Jslipscomb (talk) 16:32, 19 October 2024 (UTC)