Chemistry Forums for Students > Physical Chemistry Forum

Cyanide as a Lewis Base

(1/2) > >>

Varlam:
From which orbital of cyanide (CN-) an electron pair is donated to a lewis acid?

Hybridization of carbon in cyanide is sp. The two pi bonds are formed by 2Px + 2Px, and 2Py + 2Py.

So is the donated electron pair from 2s orbital of nitrogen? or from sp orbital of carbon?

Borek:

--- Quote from: Varlam on June 26, 2019, 01:07:13 AM ---So is the donated electron pair from 2s orbital of nitrogen? or from sp orbital of carbon?
--- End quote ---

I would say neither. Atomic orbitals (especially those from valence shells) combine creating molecular orbitals, so it doesn't make much sense to assign electrons to specific atoms.

Corribus:
Totally. In the MO point of view, about the best you can say is that the valence electrons come from an orbital that has a majority fraction of carbon character, meaning the orbital contains more carbon atomic orbital character than nitrogen character.

https://chemistry.stackexchange.com/questions/18449/cyanide-ion-non-bonding-lone-pair

Babcock_Hall:
Suppose one wished to use a model based on hybridized orbitals.  I would suppose that the unshared pair on the carbon atom are in its sp orbital.  Likewise the unshared pair on nitrogen is in its sp orbital, not an s orbital.

Varlam:

--- Quote from: Borek on June 26, 2019, 03:03:47 AM ---
--- Quote from: Varlam on June 26, 2019, 01:07:13 AM ---So is the donated electron pair from 2s orbital of nitrogen? or from sp orbital of carbon?
--- End quote ---

I would say neither. Atomic orbitals (especially those from valence shells) combine creating molecular orbitals, so it doesn't make much sense to assign electrons to specific atoms.

--- End quote ---

I think not all orbitals of valence shell combine in the case of cyanide. Nitrogen has a lone pair which does not involve in covalent bonding. Carbon has a pair of electrons too which don't get shared.

Navigation

[0] Message Index

[#] Next page