FROM AN EXTENDED IONIC ORDERING IN THE PURE MOLTEN-SALT KCL TO A NEW AND LOCALIZED IONIC ORDERING IN THE K0.3(KCL)0.7 MIXTURE - A NEUTRON-SCATTERING INVESTIGATION

The microscopic structure of the system K(x)(KCl)(1-x) in the salt ric h domain (x = 0 at T = 1120K and x = 0.3 at T = 1138K) has been invest igated by neutron diffraction using the isotopic substitution techniqu e. A new short range atomic and ionic organisation observed in the fir st neighbour shell of K0.3(KCL)0.7 and charge ordering is only detecte d up to the second or third neighbours. A comparative study of the ion ic ordering in the pure salt and in the mixture is carried out. The ef fect of fluctuations of atomic concentrations detected in K0.3(KCL)-0. 7 on this new short range order is discussed.