Question

Which formula and its name combination is incorrect?

• A. \([CoCl_2(en)_2]Cl\), Dichloridobis (ethane-1, 2-diamine) cobalt(III) chloride
• B. \([Co(NH_3)_5(CO_3)]Cl\), Pentaamine carbonylcobalt (III) chloride
• C. \([Pt(NH_3)_2Cl(NO_2)]\), Diamine chloridonitrito-N-platinum(II)
• D. \( K_3[Cr(C_2O_4)_3] \), Potassium trioxalatochromate(III)

Hint:

Be sure to recognize the difference between "carbonyl" (a CO group bound to metal) and "carbonate" (a CO₃ group as a ligand) when naming coordination compounds.

Answer 1

The Correct Option is B

The correct name for the complex \([Co(NH_3)_5(CO_3)]Cl\) is Pentaamine carbonatocobalt(III) chloride and not Pentaamine carbonylcobalt(III) chloride. The error lies in the use of "carbonyl" instead of "carbonate". Carbonyl refers to a ligand where a carbon atom is double-bonded to an oxygen atom, but in this case, the complex contains a carbonate ion (\( CO_3^{2-} \)), which is correctly named as carbonatocobalt(III). Thus, the correct answer is: \[ \text{(2) } [Co(NH_3)_5(CO_3)]Cl, \text{Pentaamine carbonylcobalt(III) chloride} \]