A molecular dynamics study of the atomic structure of x(MgO) 100 − x(SiO2)

A molecular dynamics study of magnesium silicate glasses was performed in order to study the local atomic environment of Mg in MgO-SiO2 with different composition. Molecular dynamics has been used to obtain models of (MgO)x(SiO2)100 − x glasses with x = 50,54,58,62 and 67, ~ 1000 atoms, and size ~ 24 Å. As expected, the models in the glass-forming region have a corner-shared tetrahedral silica network, SiO4, and Mg acts as a network modifier. The average coordination number of magnesium by oxygen was increased from 4.5 ± 0.3 to 5.0 ± 0.3 by increasing x from 50 to 67. There are ~ 5% non-network oxygen for x = 50 and the proportion increases up to 16% for x = 67. Moreover, this study reported slight changes in Si-O and Mg-O environments; however, the changes in O-O correlations were noticeable in magnesium silicate glasses at pressures up to 9 GPa.