Single phase LnNbO(4) and LnNb(0.92) W0.08O4.04 (Ln = La, Pr and Nd) were prepared via solid state reaction. The crystal structure of the materials has been investigated by X-ray diffraction and Rietveld refinement. PrNb0.92 W0.08O4.04 and NdNb0.92 W0.08O4.04 were found to have the same crystal structure as the parent phases whereas LaNb0.92W0.08O4.04 has a modulated structure. Electrical conductivity was studied by AC impedance spectroscopy. Substantial improvements in total conductivity were achieved by W doping on the B-site, with LaNb0.92 W0.08O4.04 having the highest overall conductivity of 3.0 x 10(-3) Scm(-1) at 800 degrees C. (C) 2013 Elsevier B.V. All rights reserved.