Question

Write IUPAC names of the following coordination entities:
(a) \( [Fe(en)_2Cl_2]^+ \)
(b) \( [Co(NH_3)_4(H_2O)Br]SO_4 \)
(c) \( [Ni(CN)_4]^{2- \)
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Hint:

When naming coordination complexes, follow these steps:
1. Name the ligands first, in alphabetical order, using prefixes like "di-" or "tri-" to indicate the number of identical ligands.
2. The metal comes after the ligands, with its oxidation state in Roman numerals in parentheses.
3. For anionic complexes, the metal name ends in "-ate" (e.g., nickel becomes "nickelate").
4. Use common names for neutral ligands (e.g., ammonia for \( \text{NH}_3 \), water for \( \text{H}_2\text{O} \)).

Answer 1

(a) \( [Fe(en)_2Cl_2]^+ \) In this complex:
The metal ion is \( \text{Fe}^{3+} \), representing iron in the +3 oxidation state.
\( \text{en} \) stands for ethylenediamine, a bidentate ligand.
Chlorine (Cl) acts as a 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 \( \text{Co}^{3+} \), 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 \( \text{Ni}^{2+} \), 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: \[ \text{tetra(cyanido)nickelate(II)}^{2-} \]