Final Exam

December 21, 2000

3. R. Churland, U. Frey, F. Metz, and A. E. Merbach (p. 302-307) prepared the complexes [M(CO)₂Cl₂]^– (M = Rh, Ir). Are these complexes expected to be stable by the effective atomic number rule? Why or why not? If not, what reactivity would you anticipate?

Answer:

[Rh(CO)₂Cl₂]^–: Rh⁺ is d⁸; CO is a 2-electron donor and Cl^– is also a 2-electron donor so the total electron count is 8 + 2(2) + 2(2) = 16, probably stable. [Ir(CO)₂Cl₂]^– is identical (Ir is just below Rh on the Periodic Table).