Question

The bond angle of Cr-O-Cr bond in dichromate ion is

• A. 90°
• B. 126°
• C. 109°
• D. 60°
• E. 120°

Hint:

In polyatomic ions like the dichromate ion, the bond angles are influenced by the geometry of the central atom, which is often determined by the number of bonding pairs and lone pairs around it.

Answer 1

The Correct Option is B

In the dichromate ion (\( \text{Cr}_2\text{O}_7^{2-} \)), the central chromium atoms are bonded to oxygen atoms in a bent structure. The bond angle between the Cr-O-Cr bond is determined by the geometry of the ion, which is based on the hybridization of the chromium atoms.
- The dichromate ion (\( \text{Cr}_2\text{O}_7^{2-} \)) adopts a angular or bent structure with a bond angle of 126°. - This bond angle is a result of the repulsion between the electron pairs around the chromium atoms and is consistent with the sp² hybridization of the chromium atoms.
Thus, the correct answer is (B) 126°.