8. How Does AuCl3 Behave As A Lewis Acid?

AuCl3 behaves as a Lewis acid by accepting a pair of electrons from a Lewis base to form a coordinate covalent bond. This is due to the electron-deficient nature of the gold(III) ion in AuCl3, which has an incomplete d-shell and a positive charge. The electronegative chlorine atoms surrounding the gold atom also contribute to its Lewis acidity by polarizing the metal-ligand bonds and increasing the electron deficiency of the gold ion. AuCl3 can therefore react with Lewis bases such as water, ammonia, or chloride ions to form coordination complexes.