Ce 2 Pt 8 P: A Phosphido‐platinide with Covalently Bonded Framework Polyanion

The cerium phosphido‐platinide Ce 2 Pt 8 P is synthesized by direct reaction of the elements. The crystal structure is considered as an intergrowth of structural segments with the compositions CePt 5 (CaCu 5 ‐like) and CePt 3 P (CePt 3 B‐like) along [010]. The Pt–Pt and Pt–P distances in the anionic framework are close to the ones found in CePt 5 and CePt 4 P 2 . Analysis of the chemical bonding in real space reveals the presence of a Pt–P covalently‐bonded polyanion [Pt 8 P] (consisting of PtPt 6 trigonal prisms and PPt 5 tetragonal pyramids). Cerium cations are located in the voids of the polyanionic framework. Together with CePt 5 ( m = 0, n = 1), Ce 2 Pt 8 P ( m = 1, n = 1) forms a homological series Ce n + m Pt 5 n +3 m P m . The hypothetical “CePt 3 P” ( m = 1, n = 0) with CePt 3 B‐type crystal structure is not known to date.