Ln2XCHy: Kondensierte Cluster mit zwei verschiedenen interstitiellen Atomen

Ln₂XCH_y: Condensed Clusters with Two Different Interstitial Atoms Lanthanide carbide hydride halides Ln₂XCH_y(Ln = Gd, Tb; X = Cl, Br, I; y_max = 1) are obtained by heating Ln₂XC in H₂ at 820 K. Via this reversible, topochemical reaction two different interstitial species can be incorporated at will into a condensed cluster compound for the first time. The inclusion of H is accompanied by a change from the M₆X₁₂ to the M₆X₈ cluster type. With increasing hydrogen content, electrons are gradually localized from metal—metal bonding in H-centered states finally leading to a metal-semiconductor transition. The magnetic ordering Temperatures are lowered in comparison to Ln₂XC. Hydrogenation and dehydrogenation were studied by X-ray and resistivity investigations.