Question

The IUPAC name for the complex \[[Co(N{O_2}){(N{H_3})_5}]C{l_2}\]?
(A) Nitrito-N-pentamminecobalt (III)chloride
(B) Nitrito-N-pentamminecobalt (II)chloride
(C) Pentaamminenitrito-N-cobalt (II)chloride
(D) None of the above

Answer 1

Hint: A complex compound has a metal ion at its centre with other molecules, ligands or ions surrounding it. They are attached to the central ion by coordinate (dative covalent) bonds.

Complete Step-by-Step Solution:
The given compound is a coordination compound. In order to find the IUPAC name for the given compound, we need to follow some rules:
1. Name the ions present in the compound in the order such that the name of the cation Is placed before the anion.
2. When naming within the complex ion, before we write the name of the central atom, we write the name of the ligands present.
3. The names of the ligands must be written in alphabetic order.
4. In case a certain ligand is repeated, then it needs to have certain prefixes to denote the number of times it has been repeated. The prefixes mono-, di-, tri-, are used for once, twice and thrice repetitions respectively.
5. If the ligand name is enclosed in parentheses and its number is given with the alternate prefixes bis, tris, tetrakis instead.
6. In order to denote the oxidation number of the central atom, the corresponding roman numeral must be included in a parenthesis and be written after writing the name of the central atom.
7. When the central atom is negative, then we add the suffix ‘-ate’ to the name of the central atom
Using these rules, we can name the given coordination compound as-
Ligands present - \[N{O_2}\], \[N{H_3}\], i.e. nitrito and ammine.
Central atom – Co, i.e. cobalt with oxidation state of +2
Anion – chlorine
Hence the name of the given compound can be given as Pentammienenitrito-N-cobalt (II)chloride

Hence, Option C is the correct option.

Note: IUPAC nomenclature is used to give the naming of any compound a sense of universal standardization and understanding. It helps to create a more uniform system for systematically naming compounds.