Question

A complex cation is formed by Pt (in some oxidation state) with ligands (in proper number so that coordination number of Pt becomes six). Which of the following can be its correct IUPAC name :

• A. Diammineethylenediaminedithiocyanato-S-platinum (II) ion
• B. Diammineethylenediaminedithiocyanato-S-platinate (IV) ion
• C. Diammineethylenediaminedithiocyanato-S-platinate (IV) ion
• D. Diammineethylenediaminedithiocyanato-S-platinum (IV) Ion

Answer 1

Answer: (C)

Diammineethylenediaminedithiocyanato-S-platinate (IV)

ion

Answer 2

(1) Coordination number of platinum is generally six when its oxidation state is (IV). So it is incorrect name.

(2) With type of ligand and +4 oxidation state of platinum, the complex should be cationic not anionic. So it is also incorrect name. not anion but IUPAC name is given as anion.

(3) For coordination number six, the oxidation state of Pt is +IV. So the probable formulae of the complex may be [Pt(NH3)2(en)(SCN)2]2+. So its correct IUPAC name is Diammineethylenediaminedithiocyanato-S-platinum (IV).

(4) With two NH3, two en and two SCN– ligands, the coordination number of Pt becomes eight, which is incorrect according to the question.