Naming complexes

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Katie Clark 3B
Posts: 26
Joined: Fri Sep 25, 2015 3:00 am

Naming complexes

Postby Katie Clark 3B » Wed Nov 18, 2015 11:47 pm

Can someone explain to me why the name of [Cr(en)2(H2O)Cl]Cl2 is aquachlorobis(ethylenediamine)chromium (III) chloride. I understand all of it except the bis(ethylenediamine) part. I know that the bis- is there because ethylenediamine is bidentate. But what I don't understand is why there isn't also a di- infront of ethylenediamine since the complex is (en)2. Usually you use di- to indicate that there are two of that ligand.

Chem_Mod
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Re: Naming complexes

Postby Chem_Mod » Thu Nov 19, 2015 12:10 am

bis- REPLACES di- when the ligand is polydentate, and indicates that there are two (en)'s

Katie Clark 3B
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Joined: Fri Sep 25, 2015 3:00 am

Re: Naming complexes

Postby Katie Clark 3B » Thu Nov 19, 2015 11:25 am

So if there the complex only had one (en), would the name still contain bis- since (en) is polydentate?

Johnny Yu
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Joined: Fri Sep 25, 2015 3:00 am

Re: Naming complexes

Postby Johnny Yu » Thu Nov 19, 2015 9:25 pm

You use bis-, tris-, tetrakis-, etc. when there are multiple of the same polydentate anion. If there are 2 (en) then it would be bisethylenediammine. If there is only one (en) it would be ethylenediammine. Another example is oxalato. If there is one (ox) it would be oxalato but there were 2 (ox) it will be bisoxalato. I hope this helped!


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