  Doped IrTe$_2$ is considered a platform for topological superconductivity and
therefore receives currently a lot of interest. In addition, the
superconductivity in these materials exists in close vicinity of electronic
valence bond crystals, which we explore here by means of high-pressure single
crystal x-ray diffraction in combination with density functional theory. Our
crystallographic refinements provide unprecedented information about the
structural evolution as a function of applied pressure up to 42 GPa. Using this
structural information for density functional theory calculations, we show that
the valence bond formation in IrTe$_2$ is driven by changes in the Ir-Te-Ir
bond angle. When a valence bond is formed, this bond angle decreases
drastically, leading to a stabilization of local valence bonds large enough to
push them out of a broad band continuum. This unusual local mechanism of
valence bond formation in an itinerant material provides a natural explanation
for the different valence bond orders in IrTe$_2$, implies a very strong
electron-phonon coupling and is most likely relevant for the superconductivity
as well.
