question about shape of transition metal complex

[tigiyam]

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I am just confused about how to figure out the shape of Pt(NH3)2Cl2.
Is there any brief way to get to know whether it is square planar or tetrahedral..?

Thanks in advance!

 

[ljc]

Fairly sure that if it's an unusual shape, they'll tell you. Is this from a practice MCAT question or something?

Edit: Hmm, guess there is some rhyme and reason to it. See here for a discussion of it:
http://www.thestudentroom.co.uk/showthread.php?t=1163489

 

[Pre-Med Village]

Prior knowledge of which complexes with four ligands are going form tetrahedral geometry and which will have a square planar geometry is pretty advanced. (The answer is that square planar geometry happens when the central metal has eight d electrons). I am guessing that there must be some clue in the passage that there are both cis- and trans- forms of the complex. Geometrical isomerism would only be possible with the square planar form, not the tetrahedral.

 

[Morsetlis]

I have never seen such a question before in my life.

 

[Pre-Med Village]

I have never seen such a question before in my life.

I think in one of the old paper AAMC exams coordination chemistry was used to develop questions about basic stereochemistry. It would not be out of character for an exam to present an advanced coordination chemistry topic, to get at basic knowledge in other topic areas. I think the recommendation for coordination chemistry is familiarity with nomenclature, a bit of basic knowledge about things like geometry, ligands, a hint of crystal field splitting, at least have a sense of why so many complexes are brilliantly colored, so that you know your way around, but that's about it. Not to stress about it. My sense is that AAMC would not be averse to presenting coordination chemistry as the context in a passage, but the questions would be pretty basic. To require prior knowledge of the geometry of Pt(NH3)2Cl2 seems out of character for the MCAT which is why I am thinking that the passage associated with this question must have some kind of clue.