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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: HongKongALevelboy on September 20, 2004, 11:19:21 AM

Title: Zwitterion
Post by: HongKongALevelboy on September 20, 2004, 11:19:21 AM
the definition of zwitterion is not clearly stated in my book . Can anyone definite ' zwitterion ' ? i want a concise answer . thx ^_^
Title: Re:Zwitterion
Post by: movies on September 20, 2004, 12:40:29 PM
A zwitterion is a molecule with a positive charge on one atom and a negative charge on another atom.  The most common example is probably in amino acids, which exists with the acid deprotonated and the amine protonated.  It's derived from the German zwei, meaning two ("two ions").
Title: Re:Zwitterion
Post by: Donaldson Tan on September 21, 2004, 01:25:08 AM
must the overall charge of a zwitterion be zero? eg. in the case of aminoacids, what if the molecule contain 2 -NH2 and 1 -COOH group..
Title: Re:Zwitterion
Post by: movies on September 21, 2004, 02:04:03 AM
Yes, I just double checked in my chemical dictionary and it says that it's a positive and a negative charge.
Title: Re:Zwitterion
Post by: AWK on September 21, 2004, 02:36:03 AM
Zwitterion is a specific name for net not charged molecule, so theoretically molecule may possess two positive and two negative charges.
Title: Re:Zwitterion
Post by: Donaldson Tan on September 21, 2004, 04:17:37 AM
so a zwitterion is an ion that contains at least a pair of oppositely-charged sites, such that its overall charge is zero..
Title: Re:Zwitterion
Post by: AWK on September 22, 2004, 07:33:23 AM
Any proposition for double zwitterionic amino acid (natural, but non-protein one)?