Question

The molecule in which an atom is associated with more than $8e^{-}$ is known as hyper valent molecule. All hyper valent molecules must have $d\pi -p\pi$ bonding but the molecule having back bonding need not have always $d\pi -p\pi$ bonding.
Which of the following molecule is having complete octet?

• A. $BeC{l}_2$ (dimer)
• B. $Be{H}_2$ (dimer)
• C. $Be{H}_2$ (s)
• D. $BeC{l}_2\left(s\right)$

Answer 1

The correct option is D $BeC{l}_2\left(s\right)$

This molecule have complete octet.

$Be$ have $3e^{-}$ in valence shell and both ${Cl}^{-}$ ions have $3e^{-}$

In solid or in a crystal phase vanderwaals interactions are more. So, it forms tetra coordinate structure. These vanderwaals interactions are not bonds but only the interactions between electronegative ${Cl}^{-}$ and electropositive $Be$.