Ni plate-like nanoparticles (or nanoplatelets), with a mean diameter in the range from 42 to 130 nm and a thickness of about 10 nm, were synthesized by solution reduction method. Increased crystallite-size dependences of the lattice constant and the coercivity were observed. The cause for the variation of the lattice constant and the coercivity of Ni nanoplatelets with their size was investigated, respectively. (C) 2013 Elsevier B.V. All rights reserved.