Which kind of isomerism is shown by following compounds?

\(M-SCN, M-NCS\)

Linkage isomerism

The correct answer is option 2. Linkage isomerism.

The isomerism shown by \(M-SCN\) and \(M-NCS\) is Linkage isomerism.

Linkage isomerism: This type of isomerism occurs in coordination complexes where a ligand with multiple donor atoms can bind to the central metal atom through different atoms.

\(M-SCN\) and \(M-NCS\): In these complexes, \(SCN^-\) (thiocyanate) can bind to the metal atom \((M)\) through either the sulfur \((S)\) or the nitrogen \((N)\) atom. \(M-SCN\) represents the isomer where the sulfur is bonded to the metal, and \(M-NCS\) represents the isomer where the nitrogen is bonded.

The other options are incorrect because:

Ionization isomerism: This involves different ways ions separate from a salt to form charged species in solution. It doesn't apply here as \(M-SCN\) and \(M-NCS\) are complete molecules.

Coordination isomerism: This is a broader category that can encompass linkage isomerism, but it can also include other arrangements of ligands around the central metal. Here, the focus is specifically on the bonding of the \(SCN^-\) ligand.

Solvate isomerism: This refers to isomers that differ in the number of solvent molecules attached to a complex ion. There's no indication of solvent molecules involved in \(M-SCN\) and \(M-NCS\).