Crystal structure and phase transitions of Gd(CO₃)OH studied by synchrotron PXRD

Abstract

Page s 114 isotope is concerned and deuteration is unfeasible (true for many materials, e.g. hydrogen storage materials, proton conductors, ferroelectrics, etc.). Improvements in neutron and detector technology have changed this long-standing view and a range of hydrogenous materials have now been characterised successfully with PND. [1-6] There are limitations though, naturally dependent on the 1 H content, complexity and thermal motion of the material under study. The general reduction of information inherent in PND data (from both the nature of the powder data and the often high incoherent background contribution from hydrogen-containing materials) can be partially overcome by the inclusion of single crystal X-ray diffraction (SXD) data in joint PND and SXD refinements. Also, imaging proton densities from difference Fourier maps is an old but equally powerful tool to obtain qualitative information about proton behaviour. We intend to show what appears possible today, but also point out the limitations we have found on the basis of recent datasets collected at the high intensity powder diffractometer D20 at ILL, Grenoble, and the recently upgraded HRPD at ISIS, UK. The materials studied include both inorganic and organic, and vary in 1 H content, complexity and data collection temperature.