Why do dipoles cancel out?

1 Answer
Nov 19, 2017

Well, not all of them do.....

Explanation:

Dipoles are vector quantities...and they have magnitude and direction, and are thus summed geometrically. The carbon dioxide molecule is definitely a species where there is charge separation between the carbon and the oxygen bonds....

δO=δ+C=Oδ...but given the linear structure of this molecule OCO=180, the bond dipoles cancel out upon vector addition and to give a ZERO resultant, and CO2 is thus non-polar. For +δHδOHδ+, whose structure is bent, HOH=104, and the dipoles DO NOT geometrically sum to zero. Water is thus a polar molecule....