1998 Volume 7 Pages 1141-1143
In-situ neutron powder diffraction experiments on D2O ices III and V are reported. They were performed in gas pressure cells using argon as a pressure medium. The pressure and temperature dependency of lattice constants and the deuteron ordering were established. It turns out that both ice III and V are increasingly ordered on lowering the temperature or increasing the pressure. Even close to the melting point both phases are far from being fully disordered.