About the pseudo-ternary alkali metal-thallium(I) dicyanamide systems

Abstract Metathesis reactions designed to produce nominally the pseudo-ternary ATl[N(CN)2]2 compounds (A = Li, Na, K, Rb or Cs) either yielded solid solutions or separated pseudo-binary dicyanamides next to the new compounds LiTl[N(CN)2]2 and Tl0.89(1)Cs0.11(1)[N(CN)2]. Tetragonal LiTl[N(CN)2]2 (a = 724.96(2), c = 1411.77(6) pm, Z = 4) is crystallizing isotypically with LiK[N(CN)2]2 in the space group I4/mcm, while orthorhombic Tl0.89(1)Cs0.11(1)[N(CN)2] (a = 858.19(4), b = 654.22(2), c = 738.94(4) pm, Z = 4) adopts the α-K[N(CN)2]-type structure in the space group Pbcm, which Tl[N(CN)2] itself also assumes, with the unique cationic position shared by Tl+ and Cs+ in an approximate 9:1 molar ratio. The Raman spectra of the new compounds are presented and compared to those of Tl[N(CN)2], LiK[N(CN)2]2 and LiRb[N(CN)2]2.