TIME-OF-FLIGHT NEUTRON-DIFFRACTION STUDIES ON THE DIFFERENT PHASES OF CSOH, H2O

Neutron diffraction studies on the two dimensional ice CsOH, H2O were performed at the High Resolution Powder Diffractometer at the spallation source ISIS in England. The structure at the highest temperature comprises an O (and H) disorder perpendicular to the O2H3- nets as well as an H disorder along an O-O connection line within the nets. The room temperature phase comprises ordered, corrugated nets, very likely built of ordered groups of OH- and H2O. The O order disorder transition can be assigned to the phase transition at 340 K. For a deuterated sample the different behavior of the OD- and the D2O group is determined. The OD- group must be described by a model with O off the threefold axis. O-D⋯O bridges of different strengths result. © 1990 American Institute of Physics.