H2O has very strong intermolecular forces due to the hydrogen bonds that a formed within the compound. Usually this would mean the compound has a very high melting point as a large amount of heat energy is required to overcome the forces, however H2O has a melting point of only O degrees. How come it is not a lot higher?
Melting points of the group 16 hydrides:
- Water: 0 °C
- Hydrogen sulfide: −82 °C
- Hydrogen selenide: −65.73 °C
- Hydrogen telluride: −49 °C
- Polonium hydride: −35.3 °C
In theory, as the molecules grow larger (moving down in the group), their melting poits become higher too. Water is a clear outlier due to hydrogen bonding. Its melting point is already way higher than what should be expected looking at similar molecules.