# What is the electronic structure of formaldehyde?

$\text{In formaldehyde....................?}$
The carbon centre is $s {p}^{2} - \text{hybridized.........}$
There are 4 valence electrons to distribute around carbon. Three of these electrons are $s {p}^{2} - \text{hybridized}$, and they form $2 \times C - H$, and $1 \times C - O$, bonds. The fourth carbon electron remains unhybridized, and can overlap with an oxygen electron to form a $\pi -$bond, above and below the plane of the $s {p}^{2}$ framework.
A Lewis structure of ${H}_{2} C = O$ reflects this arrangement. Most of the time it is supplied in the lab as $\text{formalin}$, an aqueous solution. $\text{Paraformaldehyde}$, ${\left(C {H}_{2} O\right)}_{3}$ is a cylic trimer, that can be used as a substitute.