Structure of LaTi2Al9O19 and reanalysis of the crystal structure of La3Ti5Al15O37

The non-perovskite compound LaTi2Al9O19 was synthesized and structurally characterized by conventional X-ray powder diffraction and shown to be isostructural with SrTi3Al8O19, as confirmed by bond-valence sum calculations. The dielectric properties of LaTi2Al9O19 at 1 MHz were measured. The crystal structure of La3Ti5Al15O37, which is referred to as the most complex structure solved ab initio from X-ray powder diffraction (XRPD) to date, is shown to be incorrect.