CHEMISTRY COMMUNITY

How is the order of each ligand name determined? ex. [Co(Nh3)5Cl]Cl penta aminne chloro cobalt (2) Why do we start with naming the center first?

The ligands are named first in alphabetic order then the metal is named followed by the oxidation state.


Hope this helps in some way!

When working from name to the formula of a molecule, does the order matter? I know that if we are given the formula and then we are asked for the name we are require to write it in alphabetical order but how does it work if we are given the name first and we are trying to figure out the formula for the molecule?

You do not need to write the formula in any order, but you do need to order the atoms of the ligand in a way that the atom of the ligand which coordinates to the metal is listed first. There is a big difference between (NC) and (CN) ligands.

What is the difference between (NC) and (CN) ligands then?

The NC ligand suggests that the nitrogen (N) is bonded to the central cation. However, the CN ligand suggests that the carbon (C) is bonded to the central cation.

I notice that when water is a ligand (looking at #31), the SSM writes its formula as H₂O for one exercise and OH₂ for another one. I know the order of the atoms matter, so which one is correct? Why?

I think that for H2O, it is already implied/understood that the oxygen (not the hydrogen) is bonded to the central cation, so writing it either way (as H2O or OH2) is fine, although I think it is better to write it as OH2. In other words, there is only one possible way for the water to bond to the central cation.

However, for something like CN, there are two possibilities: CN (cyano) and NC (isocyano). CN( cyano) implies that the carbon atom is bonded to the central ation whereas NC (isocyano) implies that the nitrogen is bonded to the central cation.