Talk:Phosphorus tribromide

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I'm wondering if there is enough material to write a separate Phosphorus pentabromide article, or if it can be lumped in with this one and called Phosphorus bromides. I suppose there will be no separate article on Phosphorus oxybromide - that it will be lumped in together with this one or a new Phosphorus pentabromide article. H Padleckas 15:06, 20 Apr 2005 (UTC)

I'd like to keep this page specific to PBr3, but I agree that PBr5 and POBr3 aren't important enough to warrant pages of their own. Maybe we should have a separate page called Phosphorus bromides? It could summarise info on this page too. OR should we have a more general page altogether on phosphorus halides and another on phosphorus oxyhalides?
By the way, I have finished for the time being, though I was rather rushing to get it finished so there are some more things I might add in the future if I had time. I'd be interested to know what complexes there are containing metals with PBr3 as a ligand, and also how PBr3 may be reacted with things like Grignards to make R-PBr2 or similar, are such things done/useful? Exactly how is PBr3 used commercially, i.e. the specific reactions? I've seen it used in my old company, but I'm not breaking any secrecy agreements there! Walkerma 17:51, 20 Apr 2005 (UTC)

I don't know of any specific use for PBr3 except as a brominating agent and (rarely) as a non-aqueous solvant. Metal complexes almost certainly exist: I would look to trans-[MCl(CO)(PBr3)2] (M = Rh, Ir) for examples, then do a WoS search to find others. They will have been prepared during the research on QSAR in phosphine complexes: however, I'm sure that they're not simple to isolate, and there is a risk of thermodynamic instability towards oxidative addition of the P–Br bond. Until I'm proven wrong, I would say that they are of academic interest only. As for the reaction with Grignards, it is pratically impossible to stop the reaction before the PR3 stage, even when working with PCl3. To obtain RPX2 or R2PX, you have to use other (longer) routes, at least to my knowledge, e.g.:

PPh3 + Cl2 → PPh3Cl2 → PhPCl2 + C6H5Cl
PhPCl2 + PPh3 → 2Ph2PCl

Alkylchlorophosphines are even more complicated... Physchim62 14:13, 21 May 2005 (UTC)

Compare pics[edit]

File:Phosphorus tribromide.jpg
9985 bytes per Wikipedia image file page
File:Phosphorus tribromide.PNG
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12183 bytes per Wikimedia Commons image file page

11057 bytes per Wikimedia Commons image file page

Yes! The PNG file definitely looks sharper! You even straightened out my lone pair! (I hadn't noticed till then) Did you use Photoshop, or IrfanView? I didn't use PNG only because the file size was much bigger, and I notice that the new file is twice the size- if the sizes are the same is the quality the same? When I scan my structures in, if I save it as PNG the file comes out 4x the size. If I shrink it to the same size, then the quality (as far as I can tell) gets worse than the JPG of the same size. I will have to look into getting something that will convert over without scanning, I think. Cheers, Walkerma 21:44, 21 Apr 2005 (UTC)

I used neither Photoshop nor IrfanView. I have neither one. I just used the Microsoft Windows XP version of Paint which has actually become a fairly decent program compared to earlier versions of Paint in previous Microsoft Windows software. For this PBr3, I took your Image:Phosphorus tribromide.jpg file, copied it into a *.bmp file (from the big picture directly from the image page, not the smaller one in the Phosphorus tribromide article) using my AOL 9.0 software. Then I "cleaned up" your pic using the "Paint" software and saved it into a *.PNG file. The full sized pic is in Image:Phosphorus tribromide.PNG and the pics aboved are thumbs of these reduced to 150 px on this Talk page. I now show the file sizes in the captions. The *.PNG file is 75% bigger than the *.jpg file. I am still trying to further clean up the picture so I can further sharpen it a bit and reduce the file size. In the meantime, I will soon insert my new Image:Phosphorus pentachloride.PNG pic into Phosphorus chlorides. H Padleckas 13:06, 22 Apr 2005 (UTC)
Another new cleaned-up version of the PBr3 pic was downloaded. The full size version of the pic is a little sharper, but comparisons of the 150 px size pics don't show it. The electrons were rounded and one of the P-Br bonds was moved slightly. The file size was reduced by more than 5000 bytes (5 kB) from the previous *.PNG image file. H Padleckas 17:52, 22 Apr 2005 (UTC)

Thanks again, the new pictures look great. I have been on the phone about getting better drawing software, either ChemDraw or IsisDraw, so I can make PNG files directly. I probably need an upgrade anyway- till then I'll have to muddle through. BTW, PCl3 has a 100° bond angle, PF3 is 96.3, PI3 is 102. Walkerma 19:20, 22 Apr 2005 (UTC)

Regarding phosphorus pentabromide, I found that someone had typed some nonsense in and started an article, so I wrote a basic table + stub. Walkerma 17:24, 3 May 2005 (UTC)


The article PBR3 has been merged into this one. It's edit history at the date of merging is as follows:

For copyright reasons, please do not delete this information. Physchim62 21:14, 22 May 2005 (UTC)

GA Delisted[edit]

This article has been removed from the GA list due to excessive amounts of jargon as well as a lack of citations. this article can also benefit from the addition of a section about the history of the chemical. If you feel that this review was in error feel free to take it to WP:GA/R. Tarret 20:58, 4 August 2007 (UTC)

PBr3 reacts violently with oxygen[edit]

The article describes, "it gives an explosive reaction that forms P2O5 and Br2". I have read that PBr3 is sometimes used as a flame retardant, what contradicts with this statement in the article. Indeed PBr3 would produce bromine radicals during this reaction, which can inhibit combustion - but this would be ineffective if the reaction which gives the bromine radicals is strongly exothermic, which means it increases temperature and combustion processes again.

So which statement is true now? Is PBr3 a flammable or a flame retardant? -- (talk) 18:02, 26 October 2013 (UTC)

Thanks for catching that glitch. It cant be that bad because students and technicians have been using this reagent for decades. The prep of PBr3 does not refer to explosive tendencies. --Smokefoot (talk) 18:34, 26 October 2013 (UTC)