double/single-headed arrows

Moderators: Chem_Mod, Chem_Admin

Megan Ren 2B
Posts: 19
Joined: Fri Sep 25, 2015 3:00 am

double/single-headed arrows

Postby Megan Ren 2B » Sat Feb 20, 2016 12:30 am

I understand that a double-headed arrow indicates the transfer of two electrons and that a single headed arrow indicates the transfer of one electron, but all the diagrams in the course reader/examples done in class seem to use double-headed arrows anyway. When is it necessary to differentiate between the two and specifically draw either single or double-headed arrows?

Albert Agabekyan 1A
Posts: 18
Joined: Mon Oct 06, 2014 3:00 am

Re: double/single-headed arrows

Postby Albert Agabekyan 1A » Sat Feb 20, 2016 11:31 am

I think that the half headed arrow is one of those uncommon circumstances. For the most part, the double headed arrow will be used since I believe we will be dealing with lone pairs most of the time.

Chem_Mod
Posts: 17667
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 404 times

Re: double/single-headed arrows

Postby Chem_Mod » Mon Feb 22, 2016 4:12 am

Single electron transfers are pretty rare, but when you are solving a problem you should be aware of how many electrons are moving by comparing the two structures. That determines what arrow you use.

Mayvera Doaran 2H
Posts: 23
Joined: Fri Sep 25, 2015 3:00 am

Re: double/single-headed arrows

Postby Mayvera Doaran 2H » Tue Feb 23, 2016 5:58 pm

What would be an example of when we'd use a single-headed arrow?

samuelkharpatin2b
Posts: 55
Joined: Wed Sep 21, 2016 2:57 pm

Re: double/single-headed arrows

Postby samuelkharpatin2b » Sun Mar 05, 2017 1:04 pm

I believe we can focus mostly on using the double headed arrow for this class, and just know that the single headed arrow simply means that one electron is being transferred. The use of the one headed arrow is really rare and no problems in the organic textbook require the use of a single headed arrow. (At least the ones assigned to us).

Maddy_Larson_2J
Posts: 23
Joined: Wed Sep 21, 2016 2:59 pm

Re: double/single-headed arrows

Postby Maddy_Larson_2J » Mon Mar 06, 2017 10:00 am

A double headed arrow is used in the case when 2 electrons are getting passed. This is why we normally use a double-headed arrow. A single headed arrow is a little less common as it refers to only 1 electron getting passed. When dealing with bonds we are typically dealing with 2 electrons which is why its more common to see the double headed arrow rather than the single headed arrow. Hope this helps!

Chem_Mod
Posts: 17667
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 404 times

Re: double/single-headed arrows

Postby Chem_Mod » Mon Mar 06, 2017 11:31 am

Single headed arrows are used to show single electrons moving. This is common to reactions involving radicals, which are not covered in this class.


Return to “*Nucleophilic Substitution”

Who is online

Users browsing this forum: No registered users and 0 guests