Question

What is the IUPAC name of \(\text{K}_{3}[\text{Co}(\text{C}_{2}\text{O}_{4})_{3}]\) ?

• A. Potassium tris(oxalato)cobalt(III)
• B. Potassium tris(oxalato)cobaltate(III)
• C. Potassium trioxalatocobaltate(III)
• D. Potassium trioxalatocobalt(III)

Hint:

The complex ion is an anion, so the metal name ends in -ate with its oxidation state in brackets.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept
In naming a complex salt, the cation is named first, then the ligands in alphabetical order, then the metal. If the complex ion is an anion, the metal name ends in -ate.

Step 2: Identify the parts
The cation is \(\text{K}^{+}\) and the complex ion is \(\left[\text{Co}(\text{C}_{2}\text{O}_{4})_{3}\right]^{3-}\). The ligand oxalate is named oxalato and there are three of them, so trioxalato.

Step 3: Oxidation state
\(3(+1) + x + 3(-2) = 0\) gives \(x = +3\) for cobalt, written as (III).

Step 4: Name
Cobalt becomes cobaltate in the anion, so the name is potassium trioxalatocobaltate(III).

Final Answer:
The name is potassium trioxalatocobaltate(III). \[ \boxed{\text{(C) }\text{Potassium trioxalatocobaltate(III)}} \]