Life | The Universe | Everything | Advanced Search

	Sign in or register to join or start a new conversation.

This is the Message Centre for mad boffin: Part time House Ogre & Homework Enforcer.AKA George the ubiquitous prophet of Thing << Hello fellow scientist and thingite! Random Quotation >> Subject: Auwers-Skita Rule Posted Dec 5, 2004 by BigAl Keeper of the Glowing Pickle and Monobrows   Posting 1 Hey, MB, are you there? Do you know anything about Auwers-Skita Rule? I'm just writing a lesson on Geometric Isomerism and came across this w.r.t. But-2-enes. Id never come across this, but can understand that cis forms are more labile due to steric strain. However, my edition of Finar states that M.Pt of cis forms are lower than those of trans forms (so far, so good). Then goes on to say that in a pair of cis-trans isomers the cis has HIGHER B.Pt, density, referactice index, than trans forms,..... and has been used to elucidate configurations. Am I being completely thick and missing something here. I tried googlinmg the Rule, but couldn't find anything worthwhile. Read the First Reply to this Posting Subject: Auwers-Skita Rule Posted Dec 6, 2004 by mad boffin: Part time House Ogre & Homework Enforcer.AKA George the ubiquitous prophet of Thing This is a reply to this Posting   Posting 2 like I said it's down to polarity. Cis isomers are polar and trans non polar. If you consider the arrangement of electrons in the valence shell of the central atoms, they would tend to arange themselves as far a part as possible in the outer shell. if the atoms on the central carbons of but-2-ene are on the same side then theres a definite dipole in the molecule and the +ve and -ve centres are imbalanced leading to polarity. If the electronegativity differences accross the bonds are >0.5 but <1.7 then the molecule is polar. For symetrical molecules, sauch as trans but-2-ene, the polarities can balance each other across the central atoms leading to non polarity and all the properties associated with that. Hope this helps Read the First Reply to this Posting Subject: Auwers-Skita Rule Posted Dec 6, 2004 by BigAl Keeper of the Glowing Pickle and Monobrows This is a reply to this Posting   Posting 3 Yes it does. MB. (I must've been a bit too tired when I originally looked at it. Read the First Reply to this Posting Subject: Auwers-Skita Rule Posted Dec 6, 2004 by mad boffin: Part time House Ogre & Homework Enforcer.AKA George the ubiquitous prophet of Thing This is a reply to this Posting   Posting 4 no problems. you've had your freebie next one will cost kaching! Conversation list Conversation list

Please note that Not Panicking Ltd is not responsible for the content of any external sites listed. The content on h2g2 is created by h2g2's Researchers, who are members of the public. Unlike Edited Guide Entries, the content on this page has not necessarily been checked by a h2g2 editor. In the event that you consider anything on this page to be in breach of the site's House Rules, please click here .

About | Help | Terms of Use