IUPAC name of K3[Cr(C2O4)3] is

The correct answer is Option (3) → Potassium trioxalatochromate (III)

Coordination compounds are named by these IUPAC rules:

• The cation is named first, then the anion.

• Inside the complex, the ligands are named first, in alphabetical order, with prefixes di, tri, ... for their number. Anionic ligands end in -o: \( \ce{C2O4^{2-}} \) is oxalato, \( \ce{O^{2-}} \) is oxo, \( \ce{Cl^{-}} \) is chlorido.

• If the complex is an anion, the metal name ends in -ate (chromium becomes chromate).

• The oxidation state of the metal is given in Roman numerals in brackets after its name.

In \( \ce{K3[Cr(C2O4)3]} \), three \( \ce{K^{+}} \) ions balance the complex anion, so the complex carries a charge of −3:

    \( \displaystyle x+3(-2)=-3 \quad\Rightarrow\quad x=+3 \)

So the name is potassium trioxalatochromate(III).

NCERT (2026-27 edition):
Naming of Mononuclear Coordination Compounds – …