Incorporation of LiSbO3 into the lead-free piezoceramic composition 0.95Na(0.5)K(0.5)NbO(3)-0.05LiTaO(3) produced a change from an orthorhombic to tetragonal crystal system in samples produced by reaction-sintering. The inferred limit of solid solution along the compositional join, (0.95 - x)Na0.5K0.5NbO3-0.05LiTaO(3)-xLiSbO(3), occurred at x similar to 0.06. Differential scanning calorimetry indicated broad peaks at temperatures associated with ferroelectric-paraelectric transitions. The transition temperatures decreased with increasing values of x, up to x = 0.06. Microstructures showed secondary grain growth; a slight decrease in grain-size with increasing LiSbO3 modification was identified.