Talk:Paraffins: Difference between revisions
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::Conceptually speaking, we would be looking for graph equivalence here. Although the graph can be represented as a tree, "equivalence" allows any node in the tree to be the root, and the branches from any node can be in any order. --[[User:Rdm|Rdm]] 20:59, 5 December 2011 (UTC)
:::I think deciding to go by graph equivalence answers the isomer question. Stereo isomers have equivalent graphs and so would not be counted. This is what A000602 does. It also answers the question of physically
:::: Wait, what do you mean "cannot physically exist?" --[[User:Ledrug|Ledrug]] 01:27, 6
December 2011 (UTC)
::::: http://www-jmg.ch.cam.ac.uk/data/isomercount/
::::: Seems that when the molecules get highly branched, there's not enough room for all the parts to squeeze in close enough to bond. I don't do this kind of work myself, but these guys seem to have put some thought into it. —[[User:Sonia|Sonia]] 02:20, 6 December 2011 (UTC)
=== stereo-isomers ===
Someone (IP:79.54.58.148) has reverted part of my edit because they incorrectly think paraffins cannot have stereo-isomers. In fact they can, for example C(H)(CH<sub>3</sub>)(C<sub>2</sub>H<sub>5</sub>)(C<sub>3</sub>H<sub>7</sub>) (better known as 3-methylhexane: CH3CH2CH(CH3)CH2CH2CH3) is [http://www.wwnorton.com/college/chemistry/orgo3/ch4/2_methylhexane.htm chiral] and so exists in stereo-isomeric form. If you disagree please discuss it here before I change the page back. [[User:TobyK|TobyK]] 00:09, 1 December 2011 (UTC)
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