High pressure behaviour of synthetic leucite Rb-2[ZnSi5O12]: a combined neutron, X-ray and synchrotron powder diffraction study

Neutron, synchrotron and X-ray high pressure powder diffraction experiments on synthetic leucite, Rb-2[ZnSi5O12], were performed up to the maximum pre ssure of 22 GPa. The linear volume compressibility b = 38(2) CPa is similar to the value of analcime. A pressure-induced phase transition was found to appear at abut 0.45 GPa. T he transition is reversible, proper ferro-elastic and discontinuous. The sp ontaneous strain scales to an order parameter having E-g symmetry. Above 4. 5 GPa the structure transforms into an amorphous phase.