Structure and chemical bonding of Ce2Ge2In and Ce2Pt2In

Ce2Ge2In was synthesized by arc-melting the elements under argon. Its Mo2FeB2 type structure was refined on the basis of the single crystal data: P4/mbm, a=756.3(1), c=438.1(1) pm, wR2=0.0456, 339 F2 values and 12 variable parameters. The structure is an intergrowth of distorted AlB2 and CsCl related slabs of compositions CeGe2 and CeIn with a GeGe distance of 253 pm within the AlB2 slabs. The COHP analysis confirms strong covalent GeGe bonds, which determines the structure more than the corresponding PtPt bonds in isostructural Ce2Pt2In. The weaker PtPt bonding energy is compensated by stronger CePt interactions, which results in almost identical total ICOHP bonding energies for Ce2Pt2In and Ce2Ge2In.