Question

What is the IUPAC name of $\left[Co{\left(N{H}_3\right)}_5\left(ONO\right)\right]S{O}_4$?

• A. pentaammine nitrito-O-cobalt (III) sulphate
• B. pentaammine nitro-N-cobalt (III) sulphate
• C. pentaamine nitro-O-cobalt (III) sulphate
• D. pentaammonia nitro-O-cobalt (III) sulphate

Answer 1

Answer: (A)

pentaammine nitrito-O-cobalt (III) sulphate

$\left[Co\right(N{H}_3{)}_5\left(ONO\right)]S{O}_4$

• Here anion is $S{O}_4^{2-}$ and cation is $\left[Co\right(N{H}_3{)}_5\left(ONO\right){]}^{2+}$
  
• In co-ordination sphere, there are $5N{H}_3$ molecules, one $ONO$ molecule. $N{H}_3$ is written as ammine and $ONO$ as Nitrito.
  
• Oxidation state of cobalt $x-1=2$; $x=3$
  
• Ligand $ON{O}^{-}$ bound to cobalt from oxygen.
  
• IUPAC Name: Pentaammine nitrito-O-cobalt (III)sulphate