Chalcogenidotellurates(IV) (TeS3)2– and (TeSe3)2– by Low‐Temperature Solvothermal Synthesis from Liquid Ammonia and Methylamine

Abstract

AbstractThe novel chalcogenidotellurates(IV) [Zn(NH3)6][Zn(NH3)4]2(TeS3)3 (1), [Zn(NH3)4](TeSe3) (2), [Mn(NH3)6](TeS3) (3), [Mn(NH3)6](TeSe3) (4) and [Mn(CH3NH2)6](TeSe3) (5) were obtained by solvothermal reactions from elemental zinc or manganese, tellurium and sulfur or selenium, respectively, in liquid ammonia or methylamine. The reactions were performed in thick‐walled glass ampoules at 50 °C and give 1, 2 and 3 in quantitative yield. The yields for 4 and 5 are lower. The crystal structures consist of tetrammine, hexammine and hexakis(methylamine) complexes of divalent Zn and Mn and of trigonal‐pyramidal (TeCh3)2– (Ch = S, Se) anions. Compounds 1 (P31m) and 2 [two polymorphic forms, Cmc21 (2a) and Pca21 (2b)] crystallise in a noncentrosymmetric manner in polar structures, while 3 (P21/c), 4 (Pbca) and 5 (P21/m) are centrosymmetric. As an unique feature, the structure of 1 contains two different types of Zn ammine complexes, tetrahedral [Zn(NH3)4]2+ and octahedral [Zn(NH3)6]2+. Compound 5 contains the rare hexacoordinate complex [Mn(CH3NH2)6]2+. Raman spectra of 1 and 2 show the two expected symmetric and asymmetric valence vibrations between 350–380 cm–1 for (TeS3)2– and 215–235 cm–1 for (TeSe3)2–.