We have grown by metal-organic chemical vapour deposition a thick layer of indium nitride (1.4 mum) on a sapphire substrate using appropriate growth parameters. The substrate was then removed and the layer reduced to powder by a soft mechanical method. The resulting material was used to obtain an X-ray powder diffraction profile for completely relaxed indium nitride, i.e. without strain due to the lattice mismatch with sapphire. The diffraction measurement was made with a Phillips XPERT-Pro diffractometer, without slits, and collected using CuKalpha radiation at 300 K.;The powder pattern contains many (hkl) peaks, depending upon two lattice parameters, a and c, for the wurtzite crystal structure. A two-dimensional least squares procedure was adapted to minimize the fitting errors on the experimental data. The lattice parameters were accurately extracted and will be given here. (C) 2004 Elsevier Ltd. All rights reserved.