Europium-doped NaY(PO3)(4) single crystals have been synthesized by the flux method with sizes around 1 mm(3). The unit cell parameters at room temperature refined by X-ray powder diffraction are a = 7.1510(4)angstrom; b = 13.0070(8)angstrom; c = 9.6973(2)angstrom: beta = 90.606(3)degrees, Z = 4 with the space group P2(1)/n in monoclinic system. The present single crystals have a needle shape, they are elongated along the a crystallographic direction, and their size is in the 500 mu m-1 mm range. The linear thermal expansion tensor parameters were determined, being the maximum value along the b direction, 16.1 X 10(-6) K-1 and the minimum along the a direction being 11.7 X 10(-6) K-1. The IR vibration modes attributed to the group P-O are consistent with the crystallographic data concerning the chain aspect of the phosphate anion. This material melts incongruently at 1141 K. Intense visible emissions attributed to Eu3+ D-5(0) -> F-7(1), D-5(0) -> F-7(2) and D-5(0) -> F-7(4), electronic transitions have been observed after pumping at 355 nm at room temperature. (C) 2009 Elsevier B.V. All rights reserved.