The structure and dynamics in SiO2 and Al2O3 liquids under a wide pressure range and at temperature of 3000 K has been investigated by molecular dynamics simulation. It was found that the structure of considered liquids comprises D4, D5 and D6 domains which consist of TOx units (x = 4, 5 and 6
T is Si or Al). The volume occupied by all voids, the volume of all models, and diffusion constant can be expressed as a linear function of the fraction of TOx units. The authors found that the diffusion anomaly occurred in SiO2 liquid is caused by very high mobility of Si and O in the D5 domain compared to one in other domains.