chemkid
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Predictiing complex formation
Here a question i was struggling to answer in my last post on copper thiosulfate:
How does one predict the formation/formula/color of a transition metal complex?
As my interests turn towards transition metal chemistry this question becomes more and more essential. Complexes can easily be draw out on paper with
proper formulas, but how do know how to make these or even what color they will be so we'll know if we find them?
Chemkid
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UnintentionalChaos
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For color, you'll want to look up crystal field theory. It can't predict exactly what color, but it can give you an idea. Ligand field theory is an
"improvement" on the simple assumptions made for crystal field theory, but it is a lot more complicated and you'll need to understand molecular
orbital diagrams first, which I still haven't quite gotten the hold of.
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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ScienceSquirrel
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I have made quite a few transition metal complexes and really you are driven to the use of 'recipes'. Most of these have been devised by trial and
error and the compounds formed were identified by microanalysis and X ray crystallography etc.
Inorganic chemistry is not like organic chemistry where functional groups and retrosynthesis produces a fairly logical framework, it is much more like
a dark art.
The following is typical and easy producing nice crystals;
http://wwwchem.uwimona.edu.jm:1104/lab_manuals/c10expt15.htm...
This one is quite a bit harder but worth it for the colour changes;
http://alpha.chem.umb.edu/chemistry/ch371/CH371_Experiments/...
[Edited on 25-7-2008 by ScienceSquirrel]
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ShadowWarrior4444
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A particularly good primer on complex formation can be found in Linus Pauling's General Chemistry.
http://www.wou.edu/las/physci/ch462/tmcolors.htm may also be helpful.
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ScienceSquirrel
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These are quite easy to make and they are fundamental to the birth of coordination chemistry;
http://wwwchem.uwimona.edu.jm:1104/lab_manuals/Werner2.html
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chemkid
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I have made quiet a few complexes myself as well and will probably try out some of these ideas when i get back in the lab. I believe i have Linus
Pauling General Chemistry around here and will check that out.
I haven't quite gotten the molecular orbital diagrams either unintentional chaos. I will check out the Ligand Field theory. Thank you.
Chemkid
[Edited on 27-7-2008 by chemkid]
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