Question

IUPAC name of $N{a}_3[Co(N{O}_2{)}_6]$ is

• A. sodium cobaltinitrite
• B. sodium hexanitritocobaltate $(III)$
• C. sodium hexanitrocobalt $(III)$
• D. sodium hexanitritocobaltate $(II)$

Answer 1

Answer: (B)

First, we note that the name of the counter ion is sodium, now we write the name of the complex ion. It contains cobalt(III), so, it will be called as cobaltate(III). Also, it contains $6N{O}_2$ groups, so, it will be hexa nitrito.
Combining, we get that the name of the negative ion is hexanitritocobaltate(III) and the name of the compound becomes Sodium hexanitritocobaltate(III).