Experimental results of triplet phase determination using synchrotron radiation

Abstract

Potassium nitra-c.e {KN'0 3) exhibits complex polymorphism with seven polymorphs in the pressure range Q .• 0-4.0 GPa. We have studied this material at room temperature as a function of pressure up t:o 9.3 GPa usino enercrv dispersive pm-:der diffraction at the SERC Svnchr~'t.ron Radiation source (SRS). ~•le have confirm~d the structure of phas'2. IV r:eEined by neutron Uiffraction at o.JG GPa (Worlton et al., Physica l36B (1986) 503) t orthorhombic ?nma, z = 4. ?he compressibility measured in the range 0.3-9.3 GPa is found-co be anisotropic \•,rith the axial compression a-cios a:b:c = 1.00:0.64:0.50. The differing IT:erits o both X-!:ays and neutrons for high pressure studies are iscussed.