Structure measurements of compressed liquid boron at megabar pressures

We report on the first measurements of the structure of compressed liquid boron, as it crosses the melt line in dynamic shock-compression experiments at a pressure of 100 GPa. Temporally, spectrally and angularly resolving x-ray scattering provides an independent and accurate measurement of the compression factor 1.5 and the electron density of 4 × 10²³ cm^-3 at moderate temperatures of 0.2-1 eV. At these conditions, the elastic scattering measurements provide the structure factor and indicate the liquid compressed phase with a coordination number of 8.3 in good agreement with predictions from first-principles molecular dynamic simulations.