Science and Education Publishing American Journal of Materials Science and Engineering 1 1 2013 09 16 Ceramic Expansion by Water Layers on Magnesium Oxide: AB InitioStudy 50 53 EN Aqeel M. Ali Ali H. Al-Mowali Department of Chmistry, College of Science, University of Basrah, Basrah, Iraq AJMSE2013134 10.12691/ajmse-1-3-4 2013 07 03 2013 08 16 2013 09 16 MgO hydration is an expansive process. It is used in cement to compensate for shrinkage, but it can be harmful at higher concentrations. First-principles calculations have been used to investigate the electronic properties of the steps of the hydration of MgO using the general gradient approximation GGA functional method within density functional method (DFT). The energy bands along high symmetry directions, energy of hydration and energy of dissociation cut through various planes are presented. The first principles band structure calculations reported here were carried out using Perdew, Burke and Ernzerhof (PBE) method. The calculations have been applied to investigate water adsorption on the (001, 110, 111 and 210) surfaces of MgO crystal. The hydrated MgO surfaces show a similar band structure that of brucite material. Both molecular adsorption and dissociative adsorption have been found to occur. The MgO surfaces have different tendency to interact with water molecules, and they differ in susceptibility disintegration of expansion. The results show that the safest surface is (001) group, while the harmful surfaces are (210) and (111) groups.