All nanocrystalline samples are phase pure after synthesis and their diffractograms can be indexed with the hexagonal P63cm space group, Supp. Fig. , with trace amounts of the orthorhombic perovskite Pnma phase in some of the samples. The bulk HEO2-b and HEO5-b samples are also phase pure, while the HEO1-b sample contains both P63cm and Pnma phases. Refined lattice parameters (Table ) for all nanocrystalline materials reveal expansion of the unit cell compared to undoped and single R 3+ cation RMnO3, as expected from the larger average ionic radii of the cations incorporated in the present compositions. The increasing size of the ab-plane is correlated with increasing tolerance factors. The nanocrystalline samples have crystallite sizes ranging from 23 to 31 nm, as expected from the citric acid synthesis method, while SEM images of the bulk powders (Supp. Fig. ) show particle sizes from tens to hundreds of microns in size.