Signature properties of water: Their molecular electronic origins

Significance Water is one of the most common substances yet it exhibits anomalous properties important for sustaining life. It has been an enduring challenge to understand how a molecule of such apparent simplicity can encode for complex and unusual behavior across a wide range of pressures and temperatures. We reveal that embedding a complete hierarchy of electronic responses within the molecule allows water’s phase behavior and signature properties to emerge naturally even within a simple model. The key result is a simple and accurate, prediction of liquid–gas phase equilibria from freezing to the critical point thus establishing a direct link between molecular and condensed phase properties and a sound physical basis for a conceptually simple but broadly transferable model for water.