In [Ag(CN)_2]^ - , the number of π bonds is

Cyanide is considered, in a broad sense, to be the most potent ligand for many transition metals. The very high affinities of metals for cyanide can be attributed to its negative charge, compactness and ability to engage in $\pi$-bonding. The dicyanides \left[M(\mathrm{CN})_2\right]^{-}(M=\mathrm{Cu}, \mathrm{Ag}, \mathrm{Au})$are linear in geometry.$-\mathrm{C} \underset{2 \pi}{\stackrel{1 \sigma}{\equiv}} \mathrm{N}$Thus, two cyanide ions have$4 \pi-bonds.