# Hybrization of H in HNO [duplicate]

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There is a problem that states: Find the molecular geometry of each molecule and the hybridization of each atom in the molecule. The two molecules are HNO and HCN. I found HNO to be sp3 hybridized and HCN to be sp hybridized. However, it says that only N and O are hybridized in the first. While all three are hybridized in the second. Why is hydrogen listed as sp hybridized?

## marked as duplicate by Todd Minehardt, Jan, M.A.R., ringo, WildcatNov 24 '16 at 9:23

• That is a very good question; I can only assume an error in your book. Note that hybridisation should always be discussed on a per-atom level, and note that both the $\ce{O}$ in $\ce{HNO}$ and the $\ce{N}$ in $\ce{HCN}$ can also be assigned various possible hybridisations. P.S: Welcome to chemistry.stackexchange.com. Take a tour and refer to the help center for any questions about the site. – Jan Sep 27 '15 at 0:08

Hybridization refers to the orbitals that each atom is using to make bonds. In $\ce{HNO}$, the $\ce{N}$ and $\ce{O}$ are $sp^2$ hybridized. This means they form a sigma bond with an $sp^2$ orbital from each and the pi bond from the interaction of the non-hybridized $p$ orbital on each. The $\ce{N}$ also has a $sp^2$ orbital overlap with the $1s$ of $\ce{H}$, which forms a sigma bond. Each of the lone pairs on the $\ce{N}$ and $\ce{O}$ is in an $sp^2$ orbital.
In $\ce{HCN}$ the carbon is $sp$ hybridized, as is the $\ce{N}$. $\ce{C}$ and $\ce{N}$ form a sigma bond with $sp$ overlap, and the pi bond from the interaction of both of their non-hybridized $p$ orbitals (to form a triple bond). The lone pair of $\ce{N}$ is in an $sp$ orbital, and the $\ce{C-H}$ bond is from an $sp$ overlap with the $1s$ of $\ce{H}$.
None of these molecules have $sp^3$ hybridization.