CHEMISTRY COMMUNITY

Hello,

For hydrogen bonding, would a Nitrogen atom having two lone pairs be considered as TWO hydrogen bonding sites or one? In other words, is one atom a hydrogen bonding site or one lone pair?

Each lone pair on an N, O, of F is considered a Hydrogen bonding site.

Each lone pair is considered a single Hydrogen bonding site; so if you have an Oxygen atom with 2 lone pairs attached to it, that would be considered two H-bonding sites.

Each lone pair is a potential hydrogen bonding site, so in your case a nitrogen atom with TWO lone pairs would have TWO potential hydrogen bonding sites.

A hydrogen bond can occur for one lone pair of N,O, and F. Therefore, a nitrogen atom with 2 lone pairs can form 2 hydrogen bonds.

There are two nitrogen atoms with a lone pair each, so it makes sense for there to be two hydrogen bonding sites.

As everyone mentioned, yes, if nitrogen had two lone pairs, then those would be considered as two separate bonding sites for potential hydrogens to bind to. To answer your question, one lone pair is considered as a single hydrogen binding site.