Question

Write IUPAC names of the following coordination entities:
(a)[Fe(en)₂Cl₂]⁺
(b)[Co(NH₃)₄(H₂O)Br]SO₄
(c)[Ni(CN)₄]²⁻

Hint:

When naming coordination complexes, remember to follow these key steps:
Name the ligands first, in alphabetical order. Use prefixes like "di-", "tri-" to indicate the number of identical ligands.
The metal follows the ligands, with its oxidation state in parentheses in Roman numerals.
For anionic complexes, the metal name ends in "-ate" (e.g., nickel becomes "nickelate").
For neutral ligands, use their common names (e.g., ammonia for NH\(_3\), water for H\(_2\)O).

Answer 1

(a) \( [Fe(en)_2Cl_2]^+ \) In this complex: - The metal ion is \( \text{Fe}^{3+} \), which is iron in the +3 oxidation state. - \( \text{en} \) refers to ethylenediamine, which is a bidentate ligand. - Chlorine (Cl) is the monodentate ligand. - The overall charge of the complex is +1. The IUPAC name for this complex is: \[ \text{bis(ethylenediamine)(chlorido)iron(III)}^+ \]

(b) \( [Co(NH_3)_4(H_2O)Br]SO_4 \)
In this complex: - The metal ion is \( \text{Co}^{3+} \), which is cobalt in the +3 oxidation state. - \( \text{NH}_3 \) is ammonia, a monodentate ligand. - \( \text{H}_2\text{O} \) is water, also a monodentate ligand. - \( \text{Br} \) is bromide, a monodentate ligand. - The anion \( \text{SO}_4^{2-} \) balances the charge. The IUPAC name for this complex is: \[ \text{tetraammin(aqua)bromidocobalt(III) sulfate} \]

(c) \( [Ni(CN)_4]^{2-} \)
In this complex:
The metal ion is \( \text{Ni}^{2+} \), which is nickel in the +2 oxidation state.
\( \text{CN}^- \) is cyanide, a monodentate ligand.
The overall charge of the complex is -2.
The IUPAC name for this complex is: \[ \text{tetra(cyanido)nickelate(II)}^{2-} \]