What is the IUPAC name of Wilkinson’s catalyst, [RhCl(PPh3)3]?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Chloridotris(triphenylphosphine)rhodium(I)
All four names differ only in the Roman numeral, which gives the oxidation state of the metal. It follows from the charges of the ligands and of the whole entity.
Ligands: one \( \ce{Cl^-} \) (chlorido, charge −1) and three \( \ce{PPh3} \) (triphenylphosphine, a neutral ligand).
Charge of the entity: [RhCl(PPh3)3] has no counter ion, so it is neutral (charge 0).
Oxidation state of Rh: x + (−1) + 3(0) = 0, so x = +1, written rhodium(I).
NCERT (2026-27 edition):
5.7 Importance and Applications of Coordination Compounds – “Coordination compounds are used as catalysts for many industrial processes. Examples include rhodium complex, [(Ph3P)3RhCl], a Wilkinson catalyst, is used for the hydrogenation of alkenes.”
5.3.2 Naming of Mononuclear Coordination Compounds – “(v) Oxidation state of the metal in cation, anion or neutral coordination entity is indicated by Roman numeral in parenthesis.”