A{sub 5}TaAs{sub 4}Tl{sub 2} (A = Rb, K). Transition-metal Zintl phases with a novel complex ion: Synthesis, structure, and bonding
- Ames Lab., IA (United States)
Reactions of the Rb-Tl-As system near 500 C in tantalum containers always lead to the formation of Rb{sub 5}-TaAs{sub 4}Tl{sub 2} because of reactions with the container wall. On-stoichiometry reactions of these three elements in Ta, or of the four components in SiO{sub 2}, afford the pure compound. Rb{sub 5}TaAs{sub 4}Tl{sub 2} crystallizes in orthorhombic system, space group Pnma. The isostructural K{sub 5}TaAs{sub 4}Tl{sub 2} also exists. The main structural feature is the closed-shell polyanion TaAs{sub 4}Tl{sub 2}{sup 5{minus}} which can be viewed as the result of a reaction of a TaAs{sub 4}{sup 7{minus}} (t{sub d}) and TaAs{sub 4}Tl{sub 2}{sup 5{minus}} (D{sub 2h}) demonstrate the character of the bonding of Tl s and p to the electron-rich As. Two kinds of multicentered bonds are evident: {pi}{sub {perpendicular}} and {sigma} plus {pi}{sub {parallel}} in the plane of the TlAs{sub 2} Ta portions and 5c-4e d-p bonds within TaAs{sub 4}.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 653426
- Journal Information:
- Inorganic Chemistry, Vol. 37, Issue 16; Other Information: PBD: 10 Aug 1998
- Country of Publication:
- United States
- Language:
- English
Similar Records
Na{sub 23}K{sub 9}Tl{sub 15.3}: An unusual Zintl compound containing apparent Tl{sub 5}{sup 7{minus}}, Tl{sub 4}{sup 8{minus}}, Tl{sub 3}{sup 7{minus}}, and Tl{sup 5{minus}} anions
A{sub 15}Tl{sub 27} (A = Rb, Cs): A structural type containing both isolated clusters and condensed layers basedo n the Tl{sub 11} fragment. Syntheses, structure, properties, and band structure