Which of the following molecule has lower `v_(c-o)` (stretching vibration frequency of C-O bond) ?

Options

A. `[Pt(CO)_(2)Cl_(2)]`
B. `[PtCl_(3)(CO)]^(Ө)`
C. Both have equal `v_(c-o)`
D. None of these

Answer

B

Explanation

As C-O bond strength`uarr`, stretching frequency `""^(v)couarr` (for C-O bond) CO is a better `pi`-acceptor than `Cl^(-)` hence, `[Pt Cl_(3)(CO)]^(-)` has better back bonding and poor C-O bond strength.