ChemInform Abstract: Lattice Vibration Spectra. Part 49. Hydrogen Bonding and Phase Transitions of RbOH·H2O and CsOH·H2O Studied by IR and Raman Spectroscopy
Abstract
in the range of 95-401 K. Strong H bonds of the type HOH...OH- and much weaker H bonds in the case of OH-...OH2 groupings are the result of the different behavior of OH- ions and H2O molecules as H-bond donor and acceptor groups.
ChemInform Abstract
in the range of 95-401 K. Strong H bonds of the type HOH...OH- and much weaker H bonds in the case of OH-...OH2 groupings are the result of the different behavior of OH- ions and H2O molecules as H-bond donor and acceptor groups. This is demonstrated by the very different OH stretching modes of OH- and H2O in the room temp. modification of the trimorphic CsOH·H2O, observed for the same O...O distance of 264 pm. The phase transitions of CsOH·H2O found by XRD and thermoanalytical studies are confirmed. The temp. shift of the OH- stretching modes between 340 and 395 K of CsOH·H2O is interpreted by a Landau-type order-disorder phase transition. The halfwidths of the OH- bands obey an Arrhenius-type law. The activation energy derived for the range 340-390 K (high temp. modification of CsOH·H2O) is about 17 kJ/mol.
