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Naming Coordination Compounds

Posted: Fri Nov 18, 2016 2:35 pm
by Patrick Wilson 2B
When naming a coordination compound how can you determine the oxidation state of the metal? For example how would we tell if it is Copper(II) or Copper(III)?

Re: Naming Coordination Compounds

Posted: Fri Nov 18, 2016 3:05 pm
by Ricardo Munoz 3K
Good question!
Basically, you need to see how many other ligands are bound to the central atom (the transition metal), and see if anyone of them has a negative charge. For example, if you have the ion [CoCl3]-, you see that there are three Cl- ions. Therefore, they all have an overall charge of 3-. However, the ion itself has a charge of 1-. Therefore, you can see that the cobalt would need to have a charge of 2+ to cancel out part of the charge from the Cl- ions. Thus, it would be cobalt (II). If the coordination compound were [CoCl3], Co would have a charge of 3+, since the negative ions were cancelled out; thus, cobalt (III).
I hope my explanation helped!

Re: Naming Coordination Compounds

Posted: Fri Nov 18, 2016 5:26 pm
by michaeljwilson3
when given the name of a compound, how do you know the order in which each element goes in the molecular formula?

Re: Naming Coordination Compounds

Posted: Sat Nov 19, 2016 10:43 am
by Chem_Mod
Write the transition metal first after the first square bracket, but for this class, the order of the ligands doesn't matter when writing the formula. When given the formula and asked to name the complex, however, name the ligands in alphabetical order.

Re: Naming Coordination Compounds

Posted: Sat Nov 26, 2016 9:07 pm
by Morgan Zapasnik 1N
I have a quick follow up question about naming coordination compounds!
How do we know when to use the latin name of certain metals vs when to just use their normal names?
For example, when is iron called ferrate?
Thanks in advance!

Re: Naming Coordination Compounds

Posted: Sat Nov 26, 2016 9:42 pm
by Diana Catapusan 1N
I think you would use ferrate instead of iron when the iron atom has an overall negative charge. For example, when the overall compound that includes an iron atom is negative, you wouldn't change it to "ironate," you would change it to ferrate. There are a few other metals, like copper, that also change names. At a review session, a UA said that we might not be responsible to know all the exceptions because we have not covered those name changes in class, but I would double check on that. Hope this helps!