Structural studies of ionic solutions under critical conditions

The methods of neutron diffraction and isotopic substitution (NDIS) provide a direct means to probe the structure of a complex fluid mixture. The method is easily extended to studies under non-ambient conditions for which large sample containers can be used to withstand temperatures of up to 500 degrees C and pressures of 2000 bar. Within the past few years NDIS experiments have been performed on aqueous solutions of several salts at temperatures up to and beyond their critical states. The results show that both the aqua ion and hydrogen bond structure change appreciably with increases in temperature.