Ternary Transition Metal Acetylides A^I₂M⁰C₂ (A^I = K, Rb; M⁰ = Pd, Pt): Neutron Diffraction Studies and Electronic Properties 

Abstract

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Anomalous work function anisotropy in ternary acetylides

“…The (001) surface energies also indicate a much stronger Pd-C bond than Te-C one. While there is a σ-bond in both Pd-C and Te-C links between the 2sp 1 hybrid orbital of the C atom and the 5sp 1 hybrids of Pd and Te (all oriented along the M-C-C line) the Pd-C link is further strengthened by strong back-donation of Pd 4d shell electrons to the antibonding π-orbitals of the C 2− 2 ions, also associated with lengthening of the C-C bond 5 . Also note that Cs 2 Te (and also Cs 2 TeC 2 ) has the advantage over the formerly mentioned multi-alkali-antimonides that Cs is better bound in them allowing for longer operational lifetime 1 .…”

AISeC2H (AI=K, Rb, Cs): Crystalline Compounds with the Elusive −Se‐C≡C‐H Anion

“…We mainly achieved two series of compounds with the general compositions A I M I C 2 with A I =Li–Cs and M I =Cu, Ag, Au and A I 2 M 0 C 2 with A I =Na–Cs and M 0 =Pd, Pt . The latter are semiconductors with small indirect band gaps, whose sizes depend on the nature of the respective alkali metal ion A + . Very recently, these compounds have attracted some attention, as based on DFT calculations it was concluded that they should exhibit an anomalous anisotropy of workfunction values making them interesting candidates for possible applications as photocathodes and novel intercalation electrode materials for batteries .…”

AISeC2H (AI=K, Rb, Cs): Crystalline Compounds with the Elusive −Se‐C≡C‐H Anion

“…[8] But despite some very spectacular results [9] their work was hampered by the fact that crystal structure elucidation from powder diffraction turned out to be impossible in most cases and that the handling of many of the investigated compounds was difficult due to their highly explosive nature.I tw as again our group that was able to present the first crystal structures of ternary alkali metal transition metal acetylides containing C 2 2À anions. [15] Very recently,t hese compounds have attracted some attention, as based on DFT calculations it was concluded that they should exhibit an anomalous anisotropy of workfunction values [16] making them interesting candidates for possible applications as photocathodes [17] and novel intercalation electrode materials for batteries. [14] The latter are semiconductors with small indirect band gaps, whose sizes depend on the nature of the respective alkali metal ion A + .…”

“…[14] The latter are semiconductors with small indirect band gaps, whose sizes depend on the nature of the respective alkali metal ion A + . [15] Very recently,t hese compounds have attracted some attention, as based on DFT calculations it was concluded that they should exhibit an anomalous anisotropy of workfunction values [16] making them interesting candidates for possible applications as photocathodes [17] and novel intercalation electrode materials for batteries. [18] Even better workfunction values were calculated for ap otential Cs 2 Te C 2 compound, which was assumed to crystallize in the Na 2 PdC 2 structure type with linear ···Te-C C-Te··· chains in these calculations.…”