Comments on: How would you draw Mercury (II) Acetate

By: Barrie Walker

Barrie Walker — Tue, 19 Jan 2010 11:06:26 +0000

The second diagram (CAS Common Chemistry) is certainly wrong and non preferred. My own preference would be diagram no 3 (ChemSpider), that’s the way I have drawn them for the last 40 years (!) but I could live with the top diagram (Wiki). As I have said before the main thing is to be consistent and do all the metal acetates, propionates, benzoates etc the same !

By: Kirill Degtyarenko

Kirill Degtyarenko — Sun, 08 Nov 2009 23:14:11 +0000

The top diagram is the correct one for crystalline mercury diacetate. The middle diagram is simply wrong coz it shows uncharged acetic acid. I am not sure if the bottom structure is correct for aqueous solution: mercury diacetate only partially dissociates into acetate anion and (acetyloxy)mercury(1+) (CHEBI:49727).

By: tony yuan

tony yuan — Tue, 03 Nov 2009 14:11:57 +0000

From informatics point view, I would like have the first one as input, because it keeps more structure information for the machine to understand…

By: Andrew Sun

Andrew Sun — Wed, 28 Oct 2009 16:37:55 +0000

Chemical structures are not used to indicate the “true” actual state of being but emphasis of certain idea and concept. That’s why for instance carbon backbones are often drawn with explicit bond bars while carbon-hydrogen bonds are ignored. So there is no universal ‘best’ choice.

However, obscure or wrong valence is always not allowed. All the three diagrams clearly define the valence of all atoms so they are all okay for me.

By: Markus Sitzmann

Markus Sitzmann — Wed, 28 Oct 2009 00:28:11 +0000

I also would say the Wikipedia version is the best for Mercury (II) Acetate.

From my experience, Mercury (II) Acetate is one of these – unfortunately many, many – examples which you find in many forms in different database – and it is very hard to normalize or correct them to a unique representation – probably because it isn’t clear whether the type of Hg-O bond is ionic or covalent, or the rules are complex, or change from metal to metal or ligand/ion to ligand/ion.

By: Stuart

Stuart — Tue, 27 Oct 2009 21:09:49 +0000

That’s a good question… what do you get when you dissolve mercuric acetate in water? Do you get ions or do you get Hg(OAc)2 molecules? Mercury is a funny one, as far as I know it’s got a large soft squidgy electron cloud and does covalent bonding well – so if you’re going to make me come down off the fence, let’s go with covalent.

By: Antony Williams

Antony Williams — Tue, 27 Oct 2009 20:24:31 +0000

Stuart….what do you prefer…covalent or ionic? yes, CAS’s common chemistry is just a couple of H’s heavy

By: David Sharpe

David Sharpe — Tue, 27 Oct 2009 19:59:46 +0000

My own personal preference would be for Wikipedia style structure (perhaps with the oxidation state of the metal shown), the ChemSpider representation is the next best. While I wouldn’t describe the CAS representation as unclear, I find it much less obvious at a glance.

By: Stuart

Stuart — Tue, 27 Oct 2009 19:54:33 +0000

Top one if you like covalent mercury–oxygen bonds; bottom one if you prefer ionic. The middle one just seems a bit silly and has too many hydrogens…

By: Tophe

Tophe — Tue, 27 Oct 2009 19:25:42 +0000

Assuming the bond angle at the mercury atom (-O-Hg-O-) is ~180°, I’d go with the Wikipedia version.