Synthesis and characterization of ternary trielides Na7KTr4 [Tr=In or Tl] including [Tr4]8− Tetrahedra

Abstract

AbstractTwo new ternary trielides Na7KTr4 (Tr=In, Tl) have been prepared by classical solid‐state reaction from the elements in tantalum ampoules. Both are isostructural to Na7RbTl4 and therefore crystallize in the orthorhombic space group Pbam, Pearson symbol oP96 (a=b=16.3283(2)/16.2860(6), c=11.3094(17)/11.2771(4), V=3015.25(8)/2991.07(18), Z=8, R1, wR2=0.0249, 0.0386/0.0447, 0.0608). The trielide subunit is built by two crystallographically independent [Tr4]8− tetrahedra. 23Na‐MAS‐Nuclear Magnetic Resonance (NMR) as well as EPR spectroscopy was employed to characterize the compounds further. DOS calculations showed a (pseudo) band gap at EF for both compounds. Dissolution experiments in liquid ammonia were carried out for the two alkali metal indides Na7KIn4 and Na2In according to the chemistry of group 14 and 15 Zintl anions. After evaporating the solvent, the remaining material was analyzed by powder X‐ray diffraction and proved the formation of NaIn and NaNH2.