The recent development of ab initio simulation techniques enables us to carry out reliable simulations for liquid-state materials. As an example, we describe the results of ab initio molecular-dynamics simulations for liquid alkali-chalcogen mixtures and molten noble-metal halides. It is shown that the calculated structure factors are in good agreement with those obtained by neutron scattering experiments. We discuss the relationship between ab initio studies on liquids and neutron experiments from the viewpoint of theoretical research.