(i) size of $\mathrm{Cl}^{-}$ is large so it cannot accommodate around $\mathrm{Si}^{+4}$ due to limitation of slze
(ii) Interaction between lone pair of chloride lon and $\mathrm{Si}^{+4}$ is not very strong
$(1) $ $[Ag(NH_3)_2]^{+}$ - રેખીય
$ (2) $ $[MnCl^4]^{2-}$ - ચતુષ્ફલકીય
$(3) $ $[Cu(NH_3)_4]^{2+}$ - ચોરસ સમતલ
$(4) $ $[Ni(CN)_4]^{2-}$ - ચોરસ સમતલ