Synthesis, Crystal Structure and Properties of the New Laminar Quaternary Tellurides SrLnCuTe3 (Ln = Sm, Gd–Tm and Lu)

This paper reports for the first time on new laminar quaternary orthorhombic heterometallic tellurides SrLnCuTe3, fabrication of which has been a challenge until this work. Data crystal structure complete series strontium chalcogenides SrLnCuCh3 (Ch = S, Se, Te). Single crystals compounds were synthesized from elements by halogenide-flux method at 1070 K. The are crystallizing in two space groups Pnma (Ln Sm, Gd and Tb) Cmcm Dy–Tm Lu). For SrSmCuTe3 (a 11.4592(7), b 4.3706(3), c 14.4425(9) Å, group: Pnma) with largest lanthanoid cation, Sr2+ shows C.N. 7, whereas Sm3+ reveals diminished coordination number 6. SrLuCuTe3 4.3064(3), 14.3879(9), 11.1408(7) Cmcm) smallest numbers six realized both high-charged cations (Sr2+ Lu3+: 6). Sr2+, Ln3+, Cu+ each take independent positions. structures built distorted [CuTe4]7– tetrahedra, forming infinite chains {∞1[Cu(Te1)1/1t(Te2)1/1t(Te3)2/2e]5−} along [010] SrLnCuTe3 [100] distortion polyhedra was compared whole means τ4-descriptor four coordinating Te2– anions, revealed decrease degree decreasing radius Ln3+. octahedra [LnTe6]9– form layers {∞2[Ln(Te1)2/2(Te2)2/2(Te3)2/2]3−}. tetrahedra fuse to parallel {∞2[CuLnTe3]2−} between them, providing three-dimensionality located. In structures, center capped trigonal prisms [SrTe6+1]12−, united {∞1[Sr(Te1)2/2(Te2)3/3(Te3)2/2]4−} direction. domains existence Ba2MnS3, BaLaCuS3, Eu2CuS3 KZrCuS3 types defined Se Tb–Er) temperature range 2 up 300 K paramagnetic, without showing clear signs magnetic phase transition.