Question

Differentiate between:
(i) Double salt and Complex compound
(ii) Didentate ligand and Ambidentate ligand

Answer 1

(i) Double Salts Compared to Complex Compounds

Double salts are formed when two simple salts combine ionically. They maintain the properties of their constituent salts in solution and do not feature coordinate bonds.

An illustration of a double salt is: \[ \mathrm{K_2SO_4 \cdot Al_2(SO_4)_3} \]

Conversely, complex compounds involve a central metal ion linked to ligands via coordinate covalent bonds, where ligands furnish electron pairs to the metal.

An instance of a complex compound is: \[ [\mathrm{CoCl_2(en)_2}]SO_4 \], with "en" denoting ethylenediamine, a ligand.

(ii) Didentate Ligands Versus Ambidentate Ligands

- Didentate ligands attach to a metal atom or ion utilizing two donor atoms concurrently. Ethylenediamine (en) serves as an example, with its two nitrogen atoms bonding to the metal.

- Ambidentate ligands possess two potential donor atoms but can only coordinate through a single atom at any given moment. The thiocyanate ion \[ \mathrm{SCN^-} \] is a prime illustration. It can bond to the metal via its sulfur atom (S-bound) or its nitrogen atom (N-bound), but not simultaneously through both.