Sr0.53Ba0.47Nb2O6 (SBN53) ceramics were reactively sintered from SrNb2O6 and BaNb2O6 powders. The formation temperature decreased from 1260degreesC for unseeded samples to 1130degreesC for the samples with 15.4 wt% seeds plus 0.85 mol% V2O5 at a heating rate of 4degreesC/min. For the V2O5-free samples, the activation energy was lowered from 554 +/- 15 kJ/mol for unseeded samples to 241 +/- 17 kJ/mol for the samples with 15.4 wt% seeds. In the V2O5-containing samples, densification and phase formation occurred simultaneously. In the V2O5-free samples, however, phase formation was completed before densification. In both cases, ceramics with greater than or equal to95% relative density were obtained. In all cases, SBN53 formed directly, rather than via a variety of intermediate SBN solid solutions. The microstructure evolution was also studied.