Ni2P nanocrystal with dendritic morphologies was synthesized via a solvothermal reaction between nickel sulfate (Ni-source) and yellow phosphorous (P-source) in a mixture solution of glycol and water. X-ray powder diffraction (XRD), electron diffraction pattern (ED) and transmission electronic microscopy (TEM) studies show that the as-synthesized nanocrystals is pure Ni2P with a hexagonal phase and a dendritic morphology. The growth mechanism of Ni2P dendrites involves a special solid-solution-solid transformation as well as an Ostwald ripening process. Moreover the growth of Ni2P nanodendrites occurs at the expense of Ni2P nanospheres. The effects of experimental conditions such as the volume ratio of glycol to water and solvothermal temperature on the final products were also discussed. (c) 2007 Elsevier B.V. All rights reserved.