Structure and stability of medium-sized (ZnS)_n (n=24,28,36,and 48) clusters are investigated by using first-principles approaches.A number of starting configurations for structural motifs were generated from handmade construction with chemical intuition and cut from bulk crystal.They are optimized via density functional theory(DFT).For medium-sized ZnS clusters,cage and tube structures were found the most preferred structural motifs.With increasing size,onion-like structures became more and more stable,which indicating that they are the lowest-energy structures for larger-sized clusters.Furthermore,it shows that WZ bulklike structures are more stable than ZB bulklike structures in medium-sized ZnS clusters.