Polymorphism in Liquids

摘要

Most solid-state compounds can occur in at least a few distinctly different atomic arrangements. In the case of a pure element, this behavior is termed al-lotropy. For chemical compounds, the different structural forms are called polymorphs. The occurrence of different liquid forms of the same chemical composition, with different atomic or molecular arrangements, is much less common. Two reports in this issue, by Katayama et al. on page 848 (1) and Kurita and Tanaka on page 845 (2), investigate thisunusual case, in which two differently structured liquids with the same composition can coexist in apparent equilibrium at the same temperature and pressure.