Permanent dipoles - NF3

Nitrogen can also form a fluoride, NF3, which has a permanent dipole.
Explain why NF3 has a permanent dipole.
Because:
N^(delta+)-F^(delta-)
The dela+ atom on one molecule attracts the delta- atom on a neighbouring molecule, so electrostatic attractions operate between the molecules
Where does the second mark come from which is:
Dipoles do not cancel
OR
NF3 is pyramidal (in words) / asymmetrical?
What does that even mean? Dipoles do not cancel?

Reply 1

krisshP

14

Yeah, dipoles are a bit like vectors with magnitude and direction. Note how the arrow points towards the delta- direction. Look at the pictures here, one relates to the NF3 molecule

http://arab-training.net/vb/t13643.html
Asymmetrical is the opposite of symmetrical. NF3 has this this property, look at its picture on that above link.

(edited 10 years ago)

Reply 2

TSR George

OP

17

Original post by krisshP

Yeah, dipoles are a bit like vectors with magnitude and direction. Note how the arrow points towards the delta- direction. Look at the pictures here, one relates to the NF3 molecule

http://arab-training.net/vb/t13643.html
Asymmetrical is the opposite of symmetrical. NF3 has this this property, look at its picture on that above link.

How does it's shape explain why there's a permanent dipole, though? D:

Reply 3

krisshP

14

Go to the bottom on this page
http://www.chemguide.co.uk/atoms/bonding/vdw.html

Note the symmetrical structure of CCl4, allowing the dipoles to cancel out.

Reply 4

TSR George

OP

17

Original post by krisshP

Go to the bottom on this page
http://www.chemguide.co.uk/atoms/bonding/vdw.html

Note the symmetrical structure of CCl4, allowing the dipoles to cancel out.