The IUPAC name for the complex $\left[\mathrm{Co}\left(\mathrm{NO}_{2}\right)\left(\mathrm{NH}_{3}\right)_{5}\right] \mathrm{Cl}_{2}$ is

(D) pentaammine nitrito-N-cobalt (III) chloride

(A) nitrito-N-pentaamminecobalt (III) chloride

(B) nitrito-N-pentaamminecobalt (II) chloride

(C) pentaammine nitrito-N-cobalt (II) chloride

JEE Main · 2006 · 30 Apr 2006 · Offline · Coordination Compounds

The IUPAC name for the complex

[Co (NO_{2}) (NH_{3})_{5}] Cl_{2}

(A)nitrito-N-pentaamminecobalt (III) chloride
(B)nitrito-N-pentaamminecobalt (II) chloride
(C)pentaammine nitrito-N-cobalt (II) chloride
(D)pentaammine nitrito-N-cobalt (III) chloride✓ Correct

Answer: (D)

Solution

In naming a coordination compound the ligands are cited alphabetically before the metal, and the metal's oxidation state is written in roman numerals. The cation

[Co (N O_{2}) (N H_{3})_{5}]^{2 +}

holds five neutral ammine ligands and one nitrito-N ligand of charge

- 1

, so to leave the cation at

+ 2

the cobalt must be

+ 3

. Ordering the ligands alphabetically, pentaammine before nitrito-N, the compound is pentaammine nitrito-N-cobalt(III) chloride.

JEE Main · 2006 · 30 Apr 2006 · Offline · Single correct option

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