Hydrogen Bonds

[Amy Luu 2G]

I am a bit confused on determining whether a molecule forms hydrogen bonds. I know it only occurs when the hydrogen is attached to either N, O, or F. What are the other requirements? For example, hydrogen bonds between different molecules. Can the H only bond to N,O,F on other molecules? Or can it bond to any as long as there is a partial negative charge?

[Brian_Ho_2B]

I am a bit confused on determining whether a molecule forms hydrogen bonds. I know it only occurs when the hydrogen is attached to either N, O, or F. What are the other requirements? For example, hydrogen bonds between different molecules. Can the H only bond to N,O,F on other molecules? Or can it bond to any as long as there is a partial negative charge?

Only when H forms an intermolecular attraction with N, O, F on other molecules can it be considered an H-bond. H can form intermolecular forces with negative partial charges of other elements besides N, O, and F, but it would just be considered "dipole-dipole" instead of h-bonding.

[Cooper Baddley 1F]

For a hydrogen bond to occur the N, O, and F also has to have a lone pair