Hydrogen Bonds

[Rohit Srinivas 2D]

I noticed during some of the homework on sapling the hydrogen bonds could be created twice on the same oxygen atom because it has two lone pairs. Are hydrogen bonds like coordinate covalent bonds, or does it have to do with the fact that each lone pair simply acts as a negative charge for positive dipoles to attract to?

[Natalie Do 3F]

I'm not quite sure either but I like to basically think as hydrogens as their separate parts: one proton and one electron, when I'm drawing out their bonds if that makes sense. Similar to what you said about treating them as an independent negative charge.

[allyssa bradley 1H]

I agree with this response! Think about the individual charges. Hydrogen bonds are most well-known on water molecules, and obviously a water molecule is a polar but stable molecule in terms of its average charge. However, with there being 2 hydrogen and 1 oxygen, the oxygen has a slight -2 charge and the hydrogens each have a slight +1 charge. In a cup/drop of water, all of these are going to match up -- for every 2 hydrogen, there will proportionately be 1 oxygen that has enough attraction charge for those 2. The same property applies even if the atoms are in other molecules, just as long as the other atom(s) the hydrogen/oxygen atom is bonded to is appropriately sharing its electrons to GIVE the atom that slight charge. For example, if oxygen or hydrogen is bonded to carbon, they are not even going to get any charge for a hydrogen bond because carbon is so stable.