The fundamental phenomena underlying the electrical conduction properties of Sr-containing LaAlO(3) perovskites are studied through DFT simulations. The most energetically favourable substitution sites for Sr in the LaAlO(3) lattice and the energetic barriers for oxygen diffusion were calculated. Ab initio molecular dynamics was used to investigate the onset of oxygen transport. Experimental characterization of this material has suggested the existence of undercoordinated Al atoms upon substitution of La with Sr. Our results confirm the existence of four- (Al(IV)) and fivefold (Al(V))-coordinated Al at the expense of the amount of sixfold-coordinated ones (Al(VI)), and explain the appearance of a small peak at 66 ppm in the (27)Al NMR spectrum.