= Solution
\b[The Hg–S interaction is expected to be stronger than Hg–N by the <hard and soft acids and bases> argument.] $\mathrm{Hg^{2+}}$ is a soft, readily polarizable Lewis acid. The sulfur end of thiocyanate is a softer and more polarizable donor than its nitrogen end, so it better matches mercury's electronic response and covalent bonding preference.
Nitrogen being more electronegative does not by itself make it the preferred donor to a soft metal. Charge concentration and polarizability are distinct properties. The extended solid can still contain Hg–N contacts that complete the bridging network; the prediction concerns their relative bonding preference, not the absence of N coordination.<Hard and Soft Acids and Bases by Ralph G. Pearson>[1963, primary classification and matching principle]{ref}
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