NEETChemistryCoordination Compounds
What is the correct IUPAC name for the coordination complex [ Co(NH₃)₅(NCS) ] Cl₂ ?
Options
- APentaamminethiocyanato-S-cobalt(III) chloride
- BPentaammineisothiocyanatocobalt(III) chloride
- CPentaamminethiocyanato-N-cobalt(III) chloride
- DPentaamminethiocyanato-N-cobalt(II) chloride
Correct answer
C. Pentaamminethiocyanato-N-cobalt(III) chloride
Step-by-step solution
The complex is [ Co(NH₃)₅(NCS) ] Cl₂ . The complex ion is a cation [ Co(NH₃)₅(NCS) ]²⁺ , so the metal is named as cobalt. The ligands are ammine ( NH₃ ) and thiocyanate ( NCS^- ). According to alphabetical order, 'ammine' is named before 'thiocyanato'. There are five ammine ligands, indicated by the prefix 'penta'. The ambidentate ligand NCS^- is coordinated through the nitrogen atom, which is indicated by 'thiocyanato-N' according to IUPAC conventions. Let the oxidation state of Co be x . The charge on ammine is 0