K11Cd2Sb5 built of an unprecedented planar CdSb3 triangle

Abstract

The novel ternary Zintl phase K₁₁Cd₂Sb₅ (1) with the unusual butterfly-shaped [Cd₂Sb₅]¹¹⁻ (1a) cluster anion has been prepared by employing an enhanced stoichiometric proportion of K atoms that act as scissors. 1a is composed of two corner-shared unprecedented planar CdSb₃ triangles that represent the first tricoordinated example of Cd unexpected for the octet rule.