INFLUENCE OF WATER-VAPOR PRESSURE AND MECHANICAL TREATMENTS ON PHASE-STABILITY IN MHXO4 AND MH2PO4 SALTS (M = K, RB, CS, NH4, X = S, SE)

Rubidium dihydrogen phosphate and cesium hydrogen sulphate are taken as examples of salts where phase transitions can be triggered by exposure to water vapour, grinding, etc. The water vapour pressure, exposure time and temperature are important parameters that determine the direction as well as the rate of the transitions. The fraction of water present in a sample is often determinative for the stability of a phase. A phase transition reported to occur for cesium hydrogen sulphate in the vicinity of 318 K is likely to be an artefact. © 1991, Taylor & Francis Group, LLC. All rights reserved.