Page 1 :
ABILITY OF © OMP ., E rhe ability Obe ome, nds is called the labili i oi QUICK oxchan,, The complexes in which th complex, Be (or Substitution) of its one or ‘ f, The complexes in which an E d Rn more ligands in its coordination sphere by other, | CRYSTAL FIELD STAR e, , We have learnt that i, , } Man octah, , “plit up. The energy of itale re Held of, , orbital results in lowering of oy 0 See Fig) Pe Wah chet ee, pital results in intecian Pa ek. “01 ieviicicsans i se, ep] ittii - sa, , py splitting of the @-orbitals rey BY +0.80.A4, The amount of. stabilization provided, Seay, CRS bs iteinwe ‘0 two levels ig called crystal field stabiliz ue, , p number Saas sikh ‘© number of electrons occupying t,, orbitals dna, , CFSE S x(-0.4 Ay) e0Ga) orbitals, then, , , , , , , , , , , , , , , , , , , , , For ae Ting in energy i.e., gain in stability), d? system 1, i te0 =, ») 7a pi, oe =1-0.4A,)=-0.4A,, 13) = 20, a SE = 2(- 0.4 A,) =-0.8 A,, Be system tog? eg CFSE = 3(—- 0.4 Ay) =-1.2A,, , 4 f, For d* sy Sue m onwards, the CFSE will depend whether the complex is low spin or high spin. For example,, For low spin complex, , : d‘ system pee CFSE = 4(- 0.4 A,) =- 1.6 A,, e For high spin complex, ) d* system ee CFSE = 3(— 0.4 A,) + 10.6 Ay) =— 0.6 Ay, , , , , , For d4 to d’ systems, the CFSE values are given below :, / CFSE (A,) ‘High spin, configuration, A(—0.4) t,8 ee 3(— 0.4) + 1 (0.6), , , , , , CFSE (A,), , , , , , , , , , , , , , , , , , , se =-06, 5(— 0.4) Ue Oe 3(- 0.4) + 2 (0.6), =-2.0 =), 6(— 0.4) tog! ee 4(— 0.4) + 2 (0.6), =-24 =-0.4, 6(— 0.4) + 1(0.6) tag? eA 5(— 0.4) + 2 (0.6), i iz =-18 =-0.8, system, there is only one possible arrangement and CFSE values are :, t,° ee CFSE = 6 (— 0.4) + 2(0.6), =-12A,, toy? e, CFSE = 6 (— 0.4) + 3(0.6), =-0.6A,, tog’ ef CFSE = 6 (- 0.4) + 4(0.6), =0, , onic configuration of any complex is the one which is most stable i.e., gives maximum CFSE. It may alsc, figuration may be decided on the basis of A, and pairing energy (P) ie., energy required to pair the ele:, For example, for d* low spin complex, the net CFSE will be — 1.6 A, + P, where P is the pairing energy and, SE will be — 2.0 + 2P (two electrons get paired) and so on.......