We investigated the chemical kinetics of NiCl2 reduction to apply to the synthesis of nickel nanoparticles in a tubular furnace reactor. The conversion of NiCl2 increased monotonically with reaction temperature up to 99% at 950 degrees C, and in turn, the rate constant of the reaction increased from 79 to 296 with an increase in the temperature from 800 to 950 degrees C. The reaction rate was estimated to be the first order with respect to chloride concentration, and the rate constant obeyed the Arrhenius law, of which the activation energy and pre-exponential factor were 103.79 kJ/mol and 7.34 x 10(6) min, respectively. Taking advantage of the kinetics, we synthesized crystalline nickel nanoparticles with average primary particle size ranging from 31 to 106 nm by systematically controlling the reactor temperature and chloride concentration. (C) 2005 Elsevier Ltd. All rights reserved.