X-RAY-DIFFRACTION MEASUREMENTS FOR EXPANDED LIQUID MERCURY AROUND THE METAL-NONMETAL TRANSITION REGION

The energy-dispersive X-ray diffraction measurements for expanded liquid Hg have been carried out for the first time in the density region from 13.55 to 8.78 g/cm3 including the metal-nonmetal transition region. It was found that the volume expansion of liquid Hg in the metallic region, namely down to the reduced density of about 10 g/cm3, is not accompanied by a uniform increase of interatomic distance, r1, but mainly caused by a decrease of coordination number, N1. When the transition region is approached the decrease of N1 becomes rather small and r1 starts to elongate.