The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

MO diagram of BN

I would like to ask what is the bond order of BN? If I include the s-p mixing in this MO diagram, I think the electron configuration of BN should be (1sigma)2(2sigma)2(3pi)4, then all these MO orbitals are bonding orbitals, and the bond order of BN is 4.... Am I correct?, , dfsdf
Not quite, the second MO orbital would be anti-bonding from the 2s orbital's mixing.

Also the first pi bond is named with 1 as the principle i.e. 1 σ22 σ21π4
(edited 10 years ago)
Reply 2
Avatar for yiyo
yiyo
OP
Actually, I follow MO diagram of CO to construct the MO diagram of BN..., can I use this MO diagram to construct for BN? Also, in the MO diagram of CO, is 2 sigma molecular orbital a bonding orbital, while the 3 sigma is an anti-bonding orbital?
Reply 3
Avatar for shengoc
shengoc
12
Original post by yiyo
Actually, I follow MO diagram of CO to construct the MO diagram of BN..., can I use this MO diagram to construct for BN? Also, in the MO diagram of CO, is 2 sigma molecular orbital a bonding orbital, while the 3 sigma is an anti-bonding orbital?


BN is much similar to the MO of the hypothetical diatomic carbon. you are better off if you can draw MO of the diatomic carbon and shift slightly the two initial AOs to adjust for different Zeff, hence electronegativity and also their relative energy levels.

:wink:
Reply 4
Avatar for yiyo
yiyo
OP
then is 2 sigma and 3 sigma in MO diagram of C2 bonding orbital? i am quite confused with bonding and anti-bonding....
Original post by yiyo
then is 2 sigma and 3 sigma in MO diagram of C2 bonding orbital? i am quite confused with bonding and anti-bonding....


Each time you get a combination of two atomic orbitals you get a bonding molecular orbital and an anti-bonding molecular orbital (from constructive and destructive interference respectively). Take Be2 as an example:

Spoiler



each pair of mixing s-orbitals give rise to 1 bonding (lower energy) and 1 antibonding (higher energy)sigma MO. In this case all the MO's are filled and the bond order is 0. Does that help?

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you