PbS nanocrystals using surfactant assisted mechanochemical synthesis have been prepared by co-milling of lead acetate (CH(3)COO)(2)Pb center dot 3H(2)O and sodium sulfide Na(2)S center dot 9H(2)O. The methods of XRD, FE-SEM, TEM (HRTEM), UV-vis, specific surface area measurements as well as reactivity in acidic FeCl(3) media were used for the nanocrystals characterization. The XRD patterns confirmed the presence of galena PbS (JCPDS 5-592) whatever treatment conditions were applied. The strong observable peaks indicate the highly crystalline nature in formation of PbS nanostructures where preferential crystal growth in the (2 0 0) direction after addition of ethylenediamine (EDA), sodiumdodecylsulphate (SOS) and ethylendiaminetetraacetic disodium salt dihydrate (EDH) surfactants has been observed. The surface weighted crystallite sizes 3, 8, 11 and 19 nm have been calculated from XRD data using the Warren-Averbach method for surfactant-free and/or EDA, SOS and EDH surfactants assisted mechanochemical synthesis. The leaching rate of galena PbS in acidic FeCl(3) solution has been studied. The dependence of PbS nanocrystals reactivity on preferential growth parameter is documented. The highest value of the specific rate constant of leaching, k(0)/S(A) has been obtained for the mechanochemically synthesized PbS in presence of EDH surfactant. (C) 2011 Elsevier B.V. All rights reserved.