The shock compressibility of the metal halides Cul and TlCl is investi
gated experimentally. A discontinuity on the of copper iodide at a sho
ck-load compressibility curve amplitude of 110 kbar is recorded by the
reflection method and is shown to be due to disproportionation of the
compound at the shock wavefront. The shock-wave characteristics of th
e high- and low-pressure phases are obtained. The compressibility curv
e of TlCl is found to be smooth in the given range of load parameters.