Fill in the blanks by choosing the appropriate word/words from those given in the brackets: (double salts, complex compounds, uni, bi, six, four, three, coordination, linkage, imperfect, perfect, normal, penetrating, central ion, chelating, Werner, Pauling)
`C_2O_4^(2-)` is a .......... ligand.

Explanation

To solve the question, we need to identify the type of ligand that the oxalate ion, represented as \( C_2O_4^{2-} \), is classified as.

### Step-by-Step Solution:

1. **Understanding Ligands**: Ligands are ions or molecules that can donate a pair of electrons to a central metal atom to form a coordination complex. They can be classified based on the number of donor atoms they possess.

2. **Identifying the Oxalate Ion**: The oxalate ion \( C_2O_4^{2-} \) has two oxygen atoms that can donate electron pairs.

...