Question

Select the correct I.U.P.A.C. name for $\left[Co\right(N{H}_3{)}_6\left]\right[Co\left(ONO{)}_6\right]$ :

• A. Hexaamminecobalt$\left(II\right)$ hexanitrito-O cobalt$\left(II\right)$
• B. Hexaamminecobalt$\left(III\right)$ hexanitrito-N cobaltate$\left(III\right)$
• C. Hexaamminecobaltate$\left(III\right)$ hexanitrito-O cobaltate$\left(II\right)$
• D. Hexaamminecobalt$\left(III\right)$ hexanitrito-O cobaltate$\left(III\right)$

Answer 1

The correct option is D Hexaamminecobalt$\left(III\right)$ hexanitrito-O cobaltate$\left(III\right)$

Option (D) is correct. The I.U.P.A.C. name for $\left[Co\right(N{H}_3{)}_6\left]\right[Co\left(ONO{)}_6\right]$ is hexaamminecobalt(III) hexanitrito-O cobaltate(III).

$N{H}_3$ is neutral, making the first complex positively charged overall. $ONO$ has a -1 charge, making the second complex the anion and it is bounded with cobalt with its $O$ atom. As the charge on cobalt complex in the second part is -3 so it will end with -ate followed by the charge in roman letters.