Hexagonal microprisms of yttrium hydroxide (Y(OH)(3)) with tuned diameter and height have been successfully prepared for the first time via a facile hydrothermal process using sodium citrate as the shape modifying agent. Y(OH)(3) microspheres with diameter of ca. 2.5 mu m and microtubes with an average length about 13 mu m, outer diameter about 3 mu m and tube thickness about 800 nm were also obtained in current reaction systems. The possible formation mechanism for the Y(OH)(3) microstructures was briefly proposed. Y2O3:Eu3+ (5%) microstructures with similar morphologies was obtained after thermal treatment of the as-prepared Y(OH)(3):Eu3+ microstructures at 700 degrees C for 4 h. Results show that the relative emission intensity of the Y2O3:Eu3+ microprisms is about 8 times as those of the Y2O3:Eu3+ microtubes and microspheres under excitation of 259 nm ultraviolet light. The products were characterized by XRD, SEM, and EDS. (C) 2009 Elsevier Ltd. All rights reserved.