Question

Select the IUPAC name for the following complex.

• A. Tetraamminecobalt (III)-$\mu$-dihydroxidobis(ethylenediamine) cobalt (III) chloride
• B. $\mu$-Dihydroxidotetraamminebis(ethylenediamine) dicobalt(III) chloride
• C. Tetraammine cobaltate (III)-$\mu$-dihydroxidobis(ethane-1, 2-diamine) cobalt (III) chloride
• D. Tetraamminecobalt (III)-$\mu$-dihydroxidobis(ethylenediamine) cobalt(III) tetrachloride

Answer 1

Answer: (A)

Tetraamminecobalt (III)-$\mu$-dihydroxidobis(ethylenediamine) cobalt (III) chloride

Rules for naming the coordination compound:-

(1) Ligands are named before the metal.

(2) Names of ligands are written in order of neutral, negative, positive. If there are multiple ligands of the same charge type, they are named in alphabetical order.

(3) Monodental ligand prefix: di, tri,tetra...etc. Polydentate ligands receive prefix: bis, tris, tetrakis...etc.

(4) Anions end in $-ido$. This replaces the final 'e' when the anion ends with 'ate' and replaces 'ide'.

(5) Write name of central atom/ion. If complex is anion, central atom's name eneds with '-ate'.

(6) If central atom's oxidation state needs to be specified, write it as a roman numeral in parenthesis.

(Refer to Image)

IUPAC name of this complex is:-

$⟶$ Tetraamminecobalt (III)-$\mu$-dihydroxidobis (ethylenediamine) cobalt (III) chloride.

Here $\mu$ is used to represent complex ligand and en is ethylenediamine.