Ice is a material of fundamental importance to a vast range of critical processes in geology, biology, chemistry, the atmospheric sciences and space research. From the structural perspective, several different categories of ice materials exist including hydrogen-ordered, hydrogen-disordered, stacking-disordered and amorphous ice. This talk will give an overview over recent work in all those areas while keeping an eye on the implications our research has on the various areas of scientific research for which ice is an important material.
Doping of ice with hydrochloric acid enabled us to discovered three new hydrogen-ordered phases of ice which we called ices XIII, XIV and XV. These three antiferroelectric phases complete the phase diagram of H2O in the low to medium pressure range and they have allowed us to gain detailed insights into the spectroscopic properties of H2O in the condensed state. New results on the structural relaxation properties of low-density amorphous ice will be presented and they will be discussed in the context of the still heavily-debated glass transition. Finally, the topic of stacking disorder in ice will be introduced. It will be shown how stacking disorder can be quantified by using both diffraction and spectroscopy. Furthermore, the effects of stacking disorder on the physical and chemical properties of ice will be discussed including the shapes of snowflakes.