File talk:Tetracosane structure.png

Dear Edgar 181,

Could you please explain why the geometrical conformation of the shown tetracosane is bent, instead of being a straight chain alkane?

Conversation copied from my talk page at w:en:User talk:Edgar181

Could you please explain why the geometrical conformation of the shown tetracosane is bent, instead of being a straight chain alkane? What would be more precise way for description- solid state NMR shows that there's indeed energy difference between the methylene carbons in the middle. What is your reasoning for this? Thank you —Preceding unsigned comment added by Ivs5982 (talk • contribs) 12:42, 15 June 2009 (UTC)

I have drawn File:Tetracosane structure.png in such a way that it will fit in the available space in the infobox (a linear depiction would simply be too wide). In the solid state, the bent conformation will probably be slightly higher in energy than an entirely linear conformation, but not by much, so I think it is a fair compromise to balance the need for a reasonable depiction in the confines of the infobox. In the gas phase, or in aqueous solution, some bent conformations may actually be lower in energy due to the possibility of increased van der Waals interations. Having said all that, it doesn't really matter because two-dimensional skeletal formulas are not really intended to depict ground-state conformational information anyway. -- Ed (Edgar181) 13:07, 15 June 2009 (UTC)

Hi Ed. I agree it is just a drawing, but in case anyone is interested in the conformational analysis of semi-long alkanes in the gas phase and in solution, this reference could be useful.[1] :) --Itub (talk) 13:30, 15 June 2009 (UTC)

Thanks, Itub. Unfortunately, I don't have access to that journal. But from the abstract, the statement, "The smallest n-alkane with a hairpin geometry that is lower in energy than the all-trans conformer occurs for C₂₂H₄₆" suggests that the current image at tetracosane is a good representation of a low (or perhaps lowest) energy conformation. -- Ed (Edgar181) 14:51, 15 June 2009 (UTC)