isomerism in complexes

• hoay

  4 Feb 18, 03:50

  http://pastpapers.papacambridge.com/view.php?id=Cambridge%20International%20Examinations%20%28CIE%29/AS%20and%20A%20Level/Chemistry%20%289701%29/2016%20Jun/9701_s16_qp_42.pdf

   

  For Q.4(a)(iii) the complex given does not show cis-trans. The marking scheme says  that its mirror images are superimposable. But how ? I think the mirror images are non-superimposable.  when we say non-superimposable we say with reespect to 3 -dimensional arrangement. In 3-dimensional they would be different. 

   

• UltimaOnline

  4 Feb 18, 04:09

  Originally posted by hoay:

  http://pastpapers.papacambridge.com/view.php?id=Cambridge%20International%20Examinations%20%28CIE%29/AS%20and%20A%20Level/Chemistry%20%289701%29/2016%20Jun/9701_s16_qp_42.pdf

   

  For Q.4(a)(iii) the complex given does not show cis-trans. The marking scheme says  that its mirror images are superimposable. But how ? I think the mirror images are non-superimposable.  when we say non-superimposable we say with reespect to 3 -dimensional arrangement. In 3-dimensional they would be different. 

   

  
  The mirror image is indeed superimposable onto the molecule itself. Imagine the mirror image, then rotate the mirror image 180 degrees. It becomes the molecule itself, ie. superimposable.
• hoay

  4 Feb 18, 04:14

  and if on rotating 180 it doe not match the original moleucle its non-superimposable?

  If we replace one of the  bidentate ligands with two different monodentate then there would be optical isomers and not cis-trans isomers? Is'nt ? 

• UltimaOnline

  4 Feb 18, 11:56

  Originally posted by hoay:

  and if on rotating 180 it doe not match the original moleucle its non-superimposable?

  If we replace one of the  bidentate ligands with two different monodentate then there would be optical isomers and not cis-trans isomers? Is'nt ? 

  
  Yes (but can be any degree, not necessarily 180) and yes.
• hoay

  4 Feb 18, 18:58

  If sulfato SO42- is bidentate ligand along with ethylenediamine then it has no isomers as the case with Pt complex above?

• UltimaOnline

  4 Feb 18, 19:28

  Originally posted by hoay:

  If sulfato SO42- is bidentate ligand along with ethylenediamine then it has no isomers as the case with Pt complex above?

  
  Yes.
• Galateawoodson

  25 Apr 18, 16:21

  There was an article at https://chemicalstatistician.wordpress.com/tag/non-superimposable-mirror-image/ on when mirror images are non-superimposable or take a look at http://domyhomeworkonline.net/ for a help.