What type of bond forms between a slightly positive hydrogen atom in one molecule and a slightly negative atom in another molecule?
An hydrogen bond occurs when hydrogen is bound to a strongly electronegative element, i.e. typically oxygen or fluorine, which polarizes electron density towards itself. Charge separation or polarity occurs to give
In condensed phases these dipoles line up to give a quite potent INTERMOLECULAR force; and note that this occurs between molecules. Hydrogen bonding is largely responsible for the elevated boiling points of water, ammonia, and hydrogen fluoride.