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Anne Bentley, Lewis & Clark College
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Joined: 04/01/2008 - 8:09pm

Best models for lecture demonstration of inorganic isomers?

I need to order a new model kit for general chem and my (much smaller) inorganic chemistry course.  Every spring when both courses roll around to optical and geometric isomers of inorganic coordination compounds, I am frustrated and flummoxed about how to best demonstrate them.  Particularly difficult are the chelating ligands.

 

We have the Giant Molecular Model Set, a simple ball-and-stick approach.  I've done some internet browsing to find attachments, add-ons, but without a lot of success.  I'd love to hear what others use.  (I've already tried using bicycling arm warmers as chelating ligands.  I'm getting desperate.)

 

Thanks in advance for any suggestions!

 

-Anne

Barbara Reisner, James Madison University
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Joined: 11/17/2007 - 11:01am
Anne - I was wondering if student would respond equally well to "in silico" models as they would to the physical models? I realize that the tactile is a big deal, but computer models are so nice because you can do all sorts of rotation AND the students can take them home and stare at them as well. It wouldn't surprise me if there were some great jmol examples out there already. Crystal Maker and Mercury also have free versions that students can download and play with. (Of course, I wouldn't try these with my genchem students.)
Adam R. Johnson, Harvey Mudd College
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Joined: 11/17/2007 - 10:55am

I have not had luck with modeling this either.  I've used pipe cleaners.....

 you might want to check the symmetry page at Otterbien (https://www.ionicviper.org/web-resources/symmetry-resources-otterbein-college). There is (at least) Fe(ox)3 which you could show.  Dean is also interested in adding more molecules, so if you got him a CSD reference or literature citation (or probably even x,y,z coordinates) he can (quickly) put it up on the site.  Just in time teaching!  Shameless plug for my C2 symmetric "titanium dimer" structure that he put up 12 or so hours after I requested it.  Thanks Dean!

Adam

Kurt Birdwhistell, Loyola University New Orleans
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Joined: 04/18/2008 - 9:15am

I use the Prentice Hall, Framework molecular models.  They handle chelating ligands   well.  

Octahedral, trigonal pyramid, square planar are all very easy to construct.  They do not work as well for Organic molecules like rings and such. 

Kurt

Lori Watson, Earlham College
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Joined: 11/17/2007 - 10:58am
I use the Giant Molecular Model Set along with Molecular Visions flexible model kit (the organometallic version) for symmetry/point group kinds of things, but for chelating ligands I go old school--tinker toys and vacuum tubing!  I make an octahedral (or whatever) "molecule" with Tinker toys and then connect the spokes with tubing.  Works great!
Hilary Eppley, DePauw University
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Joined: 11/17/2007 - 11:03am

We have a bunch of the MolyMod model kits (both organic and inorganic) for each faculty member plus a group supply for students to build in classes.   https://www.indigoinstruments.com/molecular_models/molymod/  I find they are OK for coordination complexes but there never seem to be enough octahedral atoms--I'd order extra!   I just build simple four atom chelating ligands generally, but I always like to build something big and floppy like EDTA and show how it can wrap around the metal.