  We report a high-pressure single-crystal synchrotron x-ray diffraction on a
LaAlO3 single crystal. The transition from rhombohedral to cubic at 14.8 GPa is
confirmed by the loss of the superstructure reflections, whose intensity shows
a linear pressure dependence, characteristic of a second-order transition. The
crystal remains cubic up to 63 GPa, the highest pressure reached, which
provides a confirmation over a very large pressure range of the general rules
for the evolution of distortions of perovskites under pressure. We give the
parameters of Birch-Murnaghan equations of state in the low- and high-pressure
phases and discuss the evolution of the bulk modulus.
