[Ge 2 ] 4− Dumbbells with Very Short Ge−Ge Distances in the Zintl Phase Li 3 NaGe 2 : A Solid‐State Equivalent to Molecular O 2
2015; Wiley; Volume: 128; Issue: 3 Linguagem: Inglês
10.1002/ange.201508044
ISSN1521-3757
AutoresLavinia M. Scherf, Antti J. Karttunen, Oliver Pecher, Pieter C. M. M. Magusin, Clare P. Grey, Thomas F. Fässler,
Tópico(s)Inorganic Chemistry and Materials
ResumoAbstract The novel ternary Zintl phase Li 3 NaGe 2 comprises alkali‐metal cations and [Ge 2 ] 4− dumbbells. The diatomic [Ge 2 ] 4− unit is characterized by the shortest Ge−Ge distance (2.390(1) Å) ever observed in a Zintl phase and thus represents the first Ge=Ge double bond under such conditions, as also suggested by the (8− N ) rule. Raman measurements support these findings. The multiple‐bond character is confirmed by electronic‐structure calculations, and an upfield 6 Li NMR shift of −10.0 ppm, which was assigned to the Li cations surrounded by the π systems of three Ge dumbbells, further underlines this interpretation. For the unperturbed, ligand‐free dumbbell in Li 3 NaGe 2 , the π‐ bonding p y and p z orbitals are degenerate as in molecular oxygen, which has singly occupied orbitals. The partially filled π‐type bands of the neat solid Li 3 NaGe 2 cross the Fermi level, resulting in metallic properties. Li 3 NaGe 2 was synthesized from the elements as well as from binary reactants and subsequently characterized crystallographically.
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