# How is hybridisation of a carbon atom determined by looking at the molecule's structure and observing the lone pair and/or sigma bond present? [duplicate]

How can I judge the hybridization of a carbon atom of any carbon containing compound just by looking at its structure? How can I say this by the help of lone pairs and sigma bonds present?

## marked as duplicate by Klaus-Dieter Warzecha, ringo, Wildcat, M.A.R. ಠ_ಠ, bonFeb 10 '16 at 10:07

Count the number of $\sigma$ bonds made by that atom, and add to that the number of lone pairs present on that atom. This number is called the steric number.
If the steric number is $2$, hybridisation is $sp$. Similarly, $3 \Rightarrow sp^{2}$, and $4 \Rightarrow sp^{3}$ hybridization.