hydrogen bondOxygen pulls the shared electrons toward itself, so the oxygen end of a water molecule is slightly negative (δ−) and the hydrogen ends slightly positive (δ+). Because the molecule is bent, those charges don't cancel. The positive hydrogen of one molecule is attracted to the negative oxygen of the next: a hydrogen bond, about a twentieth as strong as a real bond. In liquid water they form and break trillions of times a second, and they hold water together far more strongly than its small size would suggest.