[Altered State]

I want to know how is the correct IUPAC-acceptable way of representing dipole moment in a molecule draw.

I've seen the three of these options:



Most images I can look if I do google images search of dipole moments follow the rules B or C, and thats what I remember for any class I've been. I saw in a book (don't remember which one) and in some lecture powerpoints of some professors of my university from last year this B/C aswell.

But in "Inorganic Chemistry" by Housecroft, I've just read that even though this is contrary to long-established chemical practice, SI convention is to represent the arro pointing from the δ- end of the bond to the δ+ end of the bond. Is this true?
I need a reliable source, like a link to IUPAC website or document.

Really appreciate help, regards

[yemonk]

Hi,

I am new to this forum however wanted to answer you this as I am having the same issue and my conclusion is plain simple, there is no incorrect answer.

In short, this is the link to IUPAC you wanted, http://goldbook.iupac.org/E01929.html, and it is simple as the book you quoted states, the correct representation is from a positive to a negative, that is the standrd in all physics text books as well.

In chemistry I do not know the origin of how it all came to be the opposite way round, however most textbooks do use opposite facing arrows, some with arrows such as in option C of your diagram, acknowledge the fact that it should be the other way round and others just use it out of pure ignorance.

For further reading I refer you too:
1.) the wikipedia article http://en.wikipedia.org/wiki/Bond_dipole_moment
2.) and these two websites http://www.av8n.com/physics/electric-dipole.htm and http://www.av8n.com/physics/electric-dipole.htm#sec-mutations where the reasons for choosing the direction are given tehre due importance.

[OrgXemProf]

Whatever happened to the old dictum: "If it ain't broke, don't fix it" ?

[mjc123]

Somebody fixed it, although it wasn't broke.

[Dan]

I was always taught, and have always used, representation C (the crossed arrow).