Large single crystals of gadolinium hydroxide [Gd(OH)(3)] in the length of several millimeters were successfully prepared by using solid KOH assisted hydrothermal method. Gd(OH)(3) samples were characterized by X-ray diffraction (XRD), 4-circle single-crystal diffraction, Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). FESEM image shows hexagonal prism morphology for the Gd(OH)(3) large crystals. The possible growth mechanism of Gd(OH)(3) large single crystals was proposed. The photoluminescence and magnetic properties of Gd(OH)(3) species were investigated. (C) 2016 Elsevier Ltd. All rights reserved.