Chapter 1, Problem 49P

Interpretation Introduction

Interpretation:Hybridization scheme that gives best description of the carbons marked by asterisks and types of orbitals are used in these bonds should be identified. Whether the bond is expected to be stronger or weaker than an ordinary $\text{C}-\text{C}$ bond should be ascertained as well.

  

Concept introduction: $\left[\text{2}\text{.2}\text{.2}\right]\text{propellane}$ belong to class of hydrocarbons called propellane. This unstable compound has three rings composed of four carbon atoms. The bond angles are considerably strained.

In accordance with VSEPR model, if four bonds are present around the central atom the hybridization associated is ${\text{sp}}^3$ and theses four orbitals tend to stay as far as $109.5°$ from one another so as to have minimum repulsions.

Similarly, if three bonds are present around the central atom the hybridization associated is ${\text{sp}}^{\text{2}}$ and theses orbitals tend to stay as far as $120°$ from one another so as to have minimum repulsions.

The table that relates the hybridization with bond angles is as follows:

  $\begin{array}{cc}\text{Type of Hybridisation}& \text{Bond angle}\\ \text{sp}& 180°\\ {\text{sp}}^2& 120°\\ {\text{sp}}^3& 109.5°\\ {\text{sp}}^3\text{d}& 90°\text{,120 }°,180°\\ {\text{sp}}^3{\text{d}}^2& 90°\text{,}180°\end{array}$