Structural characterization of alkali halides with polyhalogen anions using single-crystal X-ray diffraction at high pressure

The bonding concepts in polyhalogen anions is of great interest because of its central importance in chemistry. However, the database of polyhalogen anions is very limited to have a general concept of their chemical bonding, formation laws, and physical properties. At the same time, considering alkali halides is acting as excellent examples of how pressure enriches chemistry and provides ideas for novel optical and energy converting materials, a huge number of theoretical calculations suggest the existence of the exciting world featuring polyhalogen anions. However, very few of them have been experimentally confirmed. Investigation of the alkali halides with polyhalogen anions with unconventional stoichiometry allows not only to develop new high-pressure fundamental chemistry, but also to produce novel materials which often possess important mechanical, optical, electronic, and other physical properties, and could be of interest for potential technological applications.