On the basis of stability of complex extity in the solution, complexes may be of two types, perfect, imperfect complexes, the stabilies depends upon the extent of dissociation which in turn depends on the strength of M-L band. The dissociation of complex may be expressed `[ML_(x)P^(+)hArrMy^(+)+xL` and eq. constant of this dissociation equilibrium is called instability constant. The stability of complex depends are EAN, charge on central atom, basic nature chelation, nature of metal ion and ligand acc. to HSAB principle
The EAN of Co in `Co(CO)_(4)` is 35. Hence it is less stable. It attains stability by

Options

A. Oxidation of Co
B. Reduction of Co
C. Dimerisation
D. Tetramerisation

Explanation

`2Co(CO)_(4)hArrCo_(2)(CO)_(8)`