Alkyl groups can delocalize both the negative and positivecharges through ion (charge)-induced dipole interaction withthe polarizable alkyl groups. This charge induced polarizationof the alkyl group to delocalize the charge is the origin of

‘inductive effect’ of the alkyl groups. The apparent less efficiencyin negative charge delocalization compared to positivecharge delocalization by a particular alkyl group is attributedto the less polarizing field strength of the anionic charge.

Different thermodynamic and kinetic aspects of the stability of mercurous nitrite discovered accidentally in 1896 by P. C. Ray’s group have been critically analysed in this review arti-cle. It has been concluded that mercurous nitrite is thermody-namically unstable but it gains the kinetic stability which may originate from the overpotential factor in the gas evolution in its redox decomposition. It may also arise from strengthen-ing the HgI–HgI bond which undergoes cleavage at the rate determining step (rds) in the disproportionation of Hg22+ orits oxidation by the one-electron oxidant like NO2−. TheHgI–HgI bond is strengthened through the formation of the rela-tively weaker HgI–O bond (i.e. nitrito linkage) compared to the HgI–N bond (i.e. nitro linkage) in mercurous nitrite.