Sr2Nb2O7 nano-powders were synthesized via a hydrothermal reaction in a NaOH solution at 120 degrees C for 48 h followed by calcination at 400 degrees C for 3 h using Sr(NO3)(2) and Nb2O5 in the nonstoichiometric 1:2 Sr:Nb molar ratio as raw materials. The synthesized materials were characterized by powder X-ray diffraction (PXRD) technique and Fourier transform infrared (FTIR) spectroscopy. To investigate the effect of concentration of the basic solutions on the morphology of the obtained materials, the morphologies of the synthesized materials were studied by field emission scanning electron microscopy (FESEM) technique. As shown by the FESEM measurements, the morphology of Sr2Nb2O7 particles changed from mono-shaped flower and rod like structures to two kind flower structures by the NaOH concentration increase from 2 to 4 M. TEM images verified the nanometer size particle formation. Ultraviolet-visible spectra analysis showed that the nanostructured Sr2Nb2O7 powder possessed strong light absorption in the ultraviolet light region. (C) 2015 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.