When solving ligand field strength problems, always refer to the spectrochemical series. Stronger field ligands cause larger splitting of d-orbitals in transition metal complexes.
\(\text{CO} < \text{en} < \text{NH}_3 < \text{C}_2\text{O}_4^{2-} < \text{S}^{2-}\)
\(\text{S}^{2-} < \text{NH}_3 < \text{en} < \text{CO} < \text{C}_2\text{O}_4^{2-}\)
\(\text{NH}_3 < \text{en} < \text{CO} < \text{S}^{2-} < \text{C}_2\text{O}_4^{2-}\)
\(\text{S}^{2-} < \text{C}_2\text{O}_4^{2-} < \text{NH}_3 < \text{en} < \text{CO}\)
Step 1: Understand the Spectrochemical Series
The spectrochemical series arranges ligands based on their field strength, which affects the splitting of d-orbitals in a coordination compound. The increasing order of ligand field strength is:
\[\text{S}^{2-} < \text{C}_2\text{O}_4^{2-} < \text{NH}_3 < \text{en} < \text{CO}.\]
Step 2: Explanation of the Order
\(\text{S}^{2-}\): Sulfide ions are weak field ligands due to their large size and low charge density.
\(\text{NH}_3\): Ammonia has higher field strength due to its ability to donate lone pair electrons.
\(\text{en}\) (Ethylenediamine): A bidentate ligand with stronger field strength than \(\text{NH}_3\).
\(\text{CO}\) (Carbon monoxide): A strong field ligand due to its \(\pi\)-back bonding capability.
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)

Cobalt chloride when dissolved in water forms pink colored complex $X$ which has octahedral geometry. This solution on treating with cone $HCl$ forms deep blue complex, $\underline{Y}$ which has a $\underline{Z}$ geometry $X, Y$ and $Z$, respectively, are
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)
A coordination compound holds a central metal atom or ion surrounded by various oppositely charged ions or neutral molecules. These molecules or ions are re-bonded to the metal atom or ion by a coordinate bond.
A coordination entity composes of a central metal atom or ion bonded to a fixed number of ions or molecules.
A molecule, ion, or group which is bonded to the metal atom or ion in a complex or coordination compound by a coordinate bond is commonly called a ligand. It may be either neutral, positively, or negatively charged.