Question

Write the IUPAC name for $[Cr{{(N{{H}_{3}})}_{5}}CO]C{{l}_{3}}$
A. CarbonatoPentaamminechromium (III) chloride
B. Pentaamminecarbonatochromium (III) chloride
C. Pentaaminecarbonatochromium (III) chloride
D. Pentaammoniacarbonatochromium (III) chloride

Answer 1

We should find the type of the ligands which are present in the coordination complex to calculate the oxidation number of the metal atom which is present in the coordination complex. We should identify the cation part and anion part also to write the IUPAC name for a coordination complex.

Complete answer:
- In the question it is given that to write the IUPAC name of the coordination complex $[Cr{{(N{{H}_{3}})}_{5}}CO]C{{l}_{3}}$ .
- In the given coordination complex the ligands present are ammonia, carbonyl and chlorine.
- We know that ammonia and carbonyl (CO) ligands are neutral in nature means their oxidation number is zero.
- Means from the inner sphere complex the oxidation state of the chromium is zero.
- Coming to the chlorine which is present in the outer sphere complex that is why chlorine is written outside the brackets on the chemical formula.
- We should know that one chlorine is going to called as chloride when it contains a negative charge in it.
- Means the cationic part of the given complex is ${{[Cr{{(N{{H}_{3}})}_{5}}CO]}^{3+}}$ and the anionic part is three moles of chloride ($C{{l}^{-}}$ ) anion.
- The IUPAC names for ammonia and carbonyl ligands are Ammine and carbonaro when they are in cation species.
- Therefore the IUPAC name of the given complex $[Cr{{(N{{H}_{3}})}_{5}}CO]C{{l}_{3}}$ is Pentaamminecarbonatochromium (III) chloride.

So, the correct option is B.

Note:
Without identifying the cationic part and anionic part we cannot write the IUPAc name of the coordination complex. The anionic part of the coordination complex is going to end with ‘ide’ in IUPAC name.