Question

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

• A. Sodium cobalt nitrate
• B. Sodium hexanitritocobaltate (III)
• C. Sodium hexanitritocobalt (III)
• D. Sodium hexanitritocobaltate (II)

Answer 1

The correct option is B Sodium hexanitritocobaltate (III)

The metal sodium always has a +1 charge and there are 3 of them. So the anion must have a -3 charge.
There are six $N{O}_2$ ligands, so this will be named hexa nitrito.
The central atom is cobalt and its an anion, hence the compound name will end with cobaltate.
The oxidation number of cobalt is +3.
So the full name will be sodium hexanitritocobaltate (III)