PHASE-EQUILIBRIA OF H2SO4, HNO3, AND HCL HYDRATES AND THE COMPOSITIONOF POLAR STRATOSPHERIC CLOUDS

Thermodynamic properties and phase equilibria behavior for the hydrate s and coexisting pairs of hydrates of common acids which exist in the stratosphere are assembled from new laboratory measurements and standa rd literature data. The analysis focuses upon solid-vapor and solid-so lid-vapor equilibria at temperatures around 200 K and includes new cal orimetric and vapor pressure data. Calculated partial pressures versus 1/T slopes for the hydrates and coexisting hydrates agree well with e xperimental data where available.