Pressure dependence of the structure of liquid group 14 elements

X-ray diffraction has been measured for liquid group 14 elements at high pressures using synchrotron radiation. Static structure factors S ( Q ) and pair distribution functions g ( r ) show different pressure dependences for liquid silicon, liquid germanium and liquid tin. In liquid silicon, a significant change in the local structure occurs between 8 and 14 GPa. In liquid germanium, an anisotropic contraction of local structure occurs continuously with increasing pressure. In liquid tin, the structure contracts almost uniformly. These pressure dependences are discussed in relation to the pressure-induced phase transitions in crystalline phases and the changes in bonding between atoms.