On the Range of Existence of the Intermetallic Compounds FeSi and PtSi

Intermetallic compounds play a key role as catalysts in numerous important chemical reactions. Iron‐ and platinum‐based intermetallic compounds have gained a lot of attention because of their advantageous properties in industrial processes and their widespread application. To understand the atomic and electronic structure as well as the catalytic properties of the compounds, it is crucial to analyze the phases and determine the parameter range (i.e., composition and temperature) over which these compounds remain stable as even minor deviations in the composition can substantially alter a compound's chemical and physical properties. This makes the exact determination of homogeneity ranges particularly critical. The range of existence of FeSi and PtSi is revisited, and for FeSi, no measurable homogeneity range is observed at 800°C, while PtSi demonstrates a narrow phase width at 825°C. Phase boundaries of the neighboring phases (Fe 3 Si, FeSi 2 , Pt 6 Si 5 , and (Si, Pt)) and their corresponding lattice parameters are reported in addition.