NEUTRON POWDER DIFFRACTION STUDIES OF SOME SUPERPROTONIC AND MIXED-CRYSTALS WITH DISORDERED HYDROGEN-BONDS

Neutron diffraction is well known as an effective tool for studying pr oton location in a crystal lattice. During the last decade, the develo pment of high-resolution powder diffractometers has provided an altern ative method to single-crystal neutron diffraction in order to obtain this detailed structural information. The powder technique is rapid an d appropriate, particularly in cases where obtaining single crystals i s technically difficult. In this paper, several examples of the study of crystals with disordered hydrogen bonds are presented using the Hig h-Resolution Powder Diffractometer, at the ISIS pulsed neutron source. These include a detailed description of the hydrogen bonding and phas e transition behaviour in CsHSO4 and in Cs3D(SeO4)(2) and recent struc tural investigations on the mixed crystal K-1-x(ND4)(x)D2PO4.