SUPERCOOLED AND SUPERHEATED WATER.

Various thermodynamic, transport and structural features of water in its metastable states, both supercooled and superheated, have been determined in recent years, and highly anomalous behavior has been found near the limiting temperatures in each case. For example, the heat capacities increase exponentially at each extreme. In the high temperature extreme this behavior is predictable from van der Waals theory, but the low temperature anomaly is not. The paper reviews these measurements, with emphasis on the more extensively studied supercooled states at normal and high pressure, and evidence is given that the low temperature anomalies can be described by expressions containing a singular temperature closely associated with the temperature of homogeneous nucleation of ice I. Refs.