[shafaifer]

V(CO)₆ does not obey the 18th electron rule - is that correct?

[T6022]

Yes, the complex don't obey to 18th electron rule.
Because che complex has 0 net charge, the oxidation state of V is (0).
Because the metal is d₅, it has got 5 electron in the outer shell, so...

5 e^- from metal + 6x2 e^- from ligand = 17 e^-

This kind of complex tend to dimerize and form metal-metal bond, as Mn₂(CO)₁₀, but in this case the atom of Vanadium is small and it can't bind another metal because his steric hinderance.