Development of a Geometric Descriptor for the Strategic Synthesis of Remeika Phases

Remeika phases, also described as pseudoperovskites, are cage-like structures with emergent properties. In this Perspective, we first cover heuristic methods used to overcome the challenges to rationalize the stability of extended solids. We highlight the important role Goldschmidt’s tolerance factor has played in enhancing research related to perovskites and their derivatives. We discuss the development of a tolerance factor for predicting the stability of intermetallic pseudoperovskites, the Remeika phases, and rationalize oxidation states in correlation with valence fluctuation. To evaluate the feasibility of the Remeika phase tolerance factor, we synthesized the new predicted compound Yb5Ru6Sn18 with a magnetic moment (μeff) of 3.2 μB/Yb. We then highlight the importance of determining the factors dictating the stability of the Remeika intermetallics.