Trivalent europium – a scarce case in intermetallics

Abstract In most intermetallic europium compounds, the Eu atoms exhibit a divalent oxidation state with a high effective magnetic moment since Eu 2+ is isoelectronic with Gd 3+ . Trivalent intermetallic Eu compounds, in contrast, are extremely scarce and under 20 examples are known to literature. This mini-review summarizes the known binary and ternary examples along with their crystal-chemical peculiarities as well as their magnetic and 151 Eu Mössbauer spectroscopic behavior. Additionally, compounds that exhibit valence phase transitions are summarized.