Quick Back-Donation Question

**plexus0208** · Nov30-09, 02:21 AM

Cr(CO)₆
Fe(CO)₅
Ni(CO)₄

Is there more back-donation (from the CO) going up OR down the above column? I always get this mixed up.

**chemisttree** · Nov30-09, 05:52 PM

Back donation is from the metal back to the ligand, not the other way as you have indicated ("from the CO").

These compounds are not isoelectronic and have different CN's. How do you want to compare the backbonding? Per ligand or per complex?