Compound en

[almaortega]

Are we expected to know what the compound en is and what it contributes to a coordination number? It's on the achieve and I remember Lavelle mentioning en being an abbreviation for a more complex compound in class, but I don't remember whether he said whether or not we are expected to know it for the final?

[Jose Angelo Grajeda 2D]

So I think the "(en)" stands for "ethylenediamine," and this is actually a bidentate ligand, where its two N atoms bond to the metal cation, contributing additional 2 to the coordination number. It's a common ligand that can be found in chelating complexes and can bind cations tightly. It would be a good idea to know it for future questions/the final, and you can see it here in this link for Naming Coordination Compounds!: https://lavelle.chem.ucla.edu/wp-conten ... pounds.pdf

Hope this helps!

[Phoebe Ko 3E]

The en ligand represents ethylenediamine, or H2NCH2CH2NH2. It is a bidentate, which means each en has two N donor atoms and is able to contribute +2 to the overall coordination number. In Achieve HW #5, the coordination number of [Co(en)2(CO)2]Br would be 6 instead of 4 because the 2 en's contribute +4 while the 2 CO's contribute +2 to the overall coordination number. I'm not sure if we need to know this for the final but I think it'll be helpful if we memorize it! I hope this was helpful!