A large new family of filled skutterudites stabilized by electron count

TL;DR

This paper reports the design and synthesis of a large new family of filled skutterudites with 43 compounds, demonstrating how electron count stabilization enables the creation of diverse, stable materials based on group 9 elements.

Contribution

It introduces a systematic approach to designing and synthesizing a broad family of filled skutterudites stabilized by electron count, expanding the known material space.

Findings

43 new filled skutterudites synthesized

Demonstrated electron count as a key stability factor

Potential to synthesize hundreds more compounds

Abstract

Based on the interplay of theory and experiment, a large new family of filled group 9 (Co, Rh and Ir) skutterudites is designed and synthesized. The new materials fill the empty cages in the structures of the known binary CoSb3, RhSb3 and IrSb3 skutterudites with alkaline, alkaline earth, and rare earth atoms to create compounds of the type AyB4X12; A atoms fill the cages to a fraction y, B are the group 9 transition metals, and X is a mixture of electronegative main group elements chosen to achieve chemical stability by adjusting the electron counts to electron-precise values. Forty-three new compounds are reported, antimony-tin and phosphorous-silicon based, with 63 compositional variations presented. The new family of compounds is large and general. The results described here can be extended to the synthesis of hundreds of new group 9 filled skutterudites.