ABSTRACT
This chapter looks at the properties of pure water. Water is the most abundant liquid on Earth. Yet it is often considered anomalous because it behaves somewhat differently from simpler and better understood liquids such as argon. Argon atoms can be modeled as Lennard–Jones spheres. Water molecules attract and repel each other like argon atoms do, but water can also form hydrogen bonds. Hydrogen bonding introduces orientation dependence into the intermolecular interactions. So, water has some properties of a normal liquid and some properties of a fluctuating tetrahedral network of hydrogen bonds. Two water molecules can form hydrogen bonds with each other. Hydrogen bonds are formed when a hydrogen donor atom is near an acceptor atom in the appropriate orientation. Water molecules can act as both donors and acceptors for hydrogen bonds. Water molecules have tetrahedral symmetry and the ability to form strong orientation-dependent hydrogen bonds.
