Chemistry and synthesis of new polar perovskites with small tolerance factors

``Usual'' perovskite-type compounds with the general formula ABO3, where A is La-Lu and Y and B is V, Cr, Mn, Fe, Co, Ni, and Cu have been attracting a lot of attention for decades. ``Exotic'' perovskites are also highly interesting because new phenomena may emerge in them. The term ``exotic'' may include compounds with unusual oxidation states, unusual ion distribution, and unusual ions at the A site and B site. Perovskites with A $=$ Sc and In have small tolerance factors, and they can be prepared only at high pressure. We will discuss ``exotic'' perovskites with A $=$ Sc and In. A limited number of compounds can be prepared at 6 GPa. Results on (A1-yMy)MnO3 (A $=$ Sc and In, M $=$ Mn, Mg, Co, and Ni), InCrO3, ScCrO3, InRhO3, ScRhO3, InNi0.5Mn0.5O3, and ScNi0.5Mn0.5O3 will be presented. We will also describe a new class of multiferroic polar materials: In-based perovskites. We show that (In1-yMy)MO3 with y $=$ 0.112-0.176 and M $=$ Fe0.5Mn0.5 is isostructural with BiFeO3 (space group R3c) and has a high ferroelectric Curie temperature; (In1-yMy)MO3 is a canted antiferromagnet with the N\'eel temperature close to RT. Our results give a significant contribution to the development of RT multiferroics and also show new ways for the preparation of perovskite-type materials.