The new binary intermetallic YbGe 2.83

Abstract

The new compound YbGe 2.83 was obtained from the reaction of Yb and Ge in liquid indium. The crystal structure of YbGe 2.83 adopts the trigonal, P3̄ m1 space group with a= b=8.3657(12) Å and c=7.0469(14) Å. The structure of YbGe 2.83 is a variant of the CaAl 2Si 2 structure type with ordered vacancies. Germanium atoms form double layers of puckered hexagons creating slabs that sandwich the Yb atoms. YbGe 2.83 can be classified as a Zintl compound with the formula Yb (2+ x)+ (Ge 2.83) (2+ x)− . The deficiencies at the Ge sites cause a mixed/intermediate valent state of ytterbium (Yb 2.35+). Valence bond sum calculations suggest an average valence of Yb ions in YbGe 2.83 of 2.51 consistent with an intermediate valence compound.