  The goal of this work is to report a systematic and balanced review of the
progress made in recent years on the high-pressure behavior of iodates, a group
of materials with multiple technological applications and peculiar behaviors
under external compression. This review article presents results obtained from
multiple characterization techniques which include: X-ray diffraction, Raman
and infrared spectroscopy, optical-absorption, resistivity, and second-harmonic
generation measurements. The discussion of the results from experiments will be
combined with density-functional theory calculations which have been shown to
be a very useful tool for the interpretation of experimental data. Throughout
the manuscript many of the phenomena observed will be connected to the presence
of a lone electron pairs of the iodine atoms in the studied iodates. The
presence of the lone electron pairs plays a crucial role in the high-pressure
behavior of iodates and it is associated with many of the phenomena discussed
here, in particular with the pressure-induced changes in the character of
iodine-oxygen bonds, which causes many physical properties to behave
nonlinearly. Towards the end of this review, a discussion of current problems
that remain unsolved is presented as well as proposals for possible avenues for
future studies.
