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Showing posts with label ISOMERISM-COORDINATION. Show all posts
Showing posts with label ISOMERISM-COORDINATION. Show all posts

Thursday, June 25, 2020

How to find number of isomers of a octahedral complex containing all different ligands for example ML2,L2,L3,L4,L5,L6 type ?

Let us consider a octahedral complexes [ML1L2L3L4L5L5]  where M is the central metal atom while L2, L2, L3 .... are six different ligands we  shall represent the ligands by smallcase letters a,b,c etc. and the metal by M. We can write 12"cis" isomers in which ligands are separated by at angle 90° and 3 "trans" isomers in which ligands are separated by 180°.

The geometrical isomers of Mabcdef areas follows.

M(L1)(L2)(L3) (L4)(L5)(L6):

"Cis" isomers: separated by 90°

(1,2)(1,3)(1,4)(1,5)

(2,3)(3,4)(4,5)(5,2)

(2,6)(3,6)(4,6)(5,6)

"Trans " isomers: separated by 180°

(1,6)(2,4)(3,5)



What are necessary and sufficient conditions for coordination complex to show "optical isomerism"?

The necessary and sufficient condition to show optical isomerism is , the complex as the whole must be asymmetrical by the absence of element of symmetry , plane of symmetry (POS) and center of symmetry ( COS).

What are condition for geometrical isomerism in coordination compounds?

Among all type of geometries in coordination compounds, only squar planer , octahedral and dodecahedral will show geometrical isomerism. The necessary and sufficient conditions is for every position of ligands there must be at least one "CIS" (separated by 90°) and one must be "TRANS" (seperated by 180°).