What is the origin of #"hydrogen-bonding"#?

Question

Mateo Aguilar · Accepted Answer

Hydrogen bonding is not due to #"anomalous expansion"#, whatever that is.

Hydrogen bonding is an intermolecular interaction observed when hydrogen is bound to a strongly electronegative atom such as fluorine, or oxygen, or nitrogen. It is largely responsible for the absurdly high normal boiling points of water, and hydrogen fluoride, #100# #""^@C#, and #19.5# #""^@C# respectively. Because of the electronegativity of the heteroatom charge separation occurs to give #""^(delta+)H-F^(delta-)# or #""^(delta-)OH_2^(delta+)#, and when the dipoles line up this constitutes a potent intermolecular force.

Serenity Allen · Answer

undefined The origin of hydrogen bonding lies in the electrostatic attraction between a hydrogen atom covalently bonded to an electronegative atom (such as nitrogen, oxygen, or fluorine) and another electronegative atom nearby. This interaction results in a weak bond known as a hydrogen bond. Hydrogen bonding is a type of dipole-dipole interaction and plays a crucial role in the structure and properties of many substances, including water, DNA, and proteins.