Perovskites of nominal composition NaCe 1−x La x Ti 2 O 6 (0≤x≤1) crystallise directly under hydrothermal conditions at 240°C. Raman spectroscopy shows distortion from the ideal cubic structure and Rietveld analysis of powder X-ray and neutron diffraction reveals that the materials represent a continuous series in rhombohedral space group R3̄c. Ce L III -edge X-ray absorption near edge structure spectroscopy shows that while the majority of cerium is present as Ce 3+ there is evidence for Ce 4+ . The paramagnetic Ce 3+ affects the chemical shift and line width of 23 Na MAS NMR spectra, which also show with no evidence for A-site ordering. 2 H MAS NMR of samples prepared in D 2 O shows the inclusion of deuterium, which IR spectroscopy shows is most likely to be as D 2 O. The deuterium content is highest for the cerium-rich materials, consistent with oxidation of some cerium to Ce 4+ to provide charge balance of A-site water.